diff --git a/vendor/github.com/drone/envsubst/funcs.go b/vendor/github.com/drone/envsubst/funcs.go
index 8df1c9876..94a3be1f2 100644
--- a/vendor/github.com/drone/envsubst/funcs.go
+++ b/vendor/github.com/drone/envsubst/funcs.go
@@ -1,11 +1,12 @@
 package envsubst
 
 import (
-	"path"
 	"strconv"
 	"strings"
 	"unicode"
 	"unicode/utf8"
+
+	"github.com/drone/envsubst/path"
 )
 
 // defines a parameter substitution function.
@@ -89,8 +90,8 @@ func toSubstr(s string, args ...string) string {
 
 	if pos+length >= len(s) {
 		// if the position exceeds the length of the
-		// string an empty string is returned
-		return ""
+		// string just return the rest of it like bash
+		return s[pos:]
 	}
 
 	return s[pos : pos+length]
@@ -183,7 +184,7 @@ func trimLongestSuffix(s string, args ...string) string {
 
 func trimShortest(s, arg string) string {
 	var shortestMatch string
-	for i :=0 ; i < len(s); i++ {
+	for i := 0; i < len(s); i++ {
 		match, err := path.Match(arg, s[0:len(s)-i])
 
 		if err != nil {
@@ -191,7 +192,7 @@ func trimShortest(s, arg string) string {
 		}
 
 		if match {
-			shortestMatch = s[0:len(s)-i]
+			shortestMatch = s[0 : len(s)-i]
 		}
 	}
 
@@ -203,7 +204,7 @@ func trimShortest(s, arg string) string {
 }
 
 func trimLongest(s, arg string) string {
-	for i :=0 ; i < len(s); i++ {
+	for i := 0; i < len(s); i++ {
 		match, err := path.Match(arg, s[0:len(s)-i])
 
 		if err != nil {
diff --git a/vendor/github.com/drone/envsubst/match.go b/vendor/github.com/drone/envsubst/match.go
deleted file mode 100644
index e2f94b580..000000000
--- a/vendor/github.com/drone/envsubst/match.go
+++ /dev/null
@@ -1,20 +0,0 @@
-package envsubst
-
-func matches() {
-
-}
-
-// alnum
-// alpha
-// ascii
-// blank
-// cntrl
-// digit
-// graph
-// lower
-// print
-// punct
-// space
-// upper
-// word
-// xdigit
diff --git a/vendor/github.com/drone/envsubst/parse/parse.go b/vendor/github.com/drone/envsubst/parse/parse.go
index ef826289d..683b44d54 100644
--- a/vendor/github.com/drone/envsubst/parse/parse.go
+++ b/vendor/github.com/drone/envsubst/parse/parse.go
@@ -174,10 +174,6 @@ func (t *Tree) parseSubstrFunc(name string) (Node, error) {
 	default:
 		return nil, ErrBadSubstitution
 	}
-	// err := t.consumeDelimiter(acceptColon, scanIdent|scanRbrack)
-	// if err != nil {
-	// 	return nil, err
-	// }
 
 	// scan arg[2]
 	{
@@ -258,8 +254,15 @@ func (t *Tree) parseReplaceFunc(name string) (Node, error) {
 		return nil, ErrBadSubstitution
 	}
 
+	// check for blank string
+	switch t.scanner.peek() {
+	case '}':
+		return node, t.consumeRbrack()
+	}
+
+	// scan arg[2]
 	{
-		param, err := t.parseParam(acceptNotClosing, scanIdent)
+		param, err := t.parseParam(acceptNotClosing, scanIdent|scanEscape)
 		if err != nil {
 			return nil, err
 		}
diff --git a/vendor/github.com/drone/envsubst/path/match.go b/vendor/github.com/drone/envsubst/path/match.go
new file mode 100644
index 000000000..9306b0c9d
--- /dev/null
+++ b/vendor/github.com/drone/envsubst/path/match.go
@@ -0,0 +1,207 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package path
+
+import (
+	"errors"
+	"unicode/utf8"
+)
+
+// ErrBadPattern indicates a globbing pattern was malformed.
+var ErrBadPattern = errors.New("syntax error in pattern")
+
+// Match reports whether name matches the shell file name pattern.
+// The pattern syntax is:
+//
+//	pattern:
+//		{ term }
+//	term:
+//		'*'         matches any sequence of non-/ characters
+//		'?'         matches any single non-/ character
+//		'[' [ '^' ] { character-range } ']'
+//		            character class (must be non-empty)
+//		c           matches character c (c != '*', '?', '\\', '[')
+//		'\\' c      matches character c
+//
+//	character-range:
+//		c           matches character c (c != '\\', '-', ']')
+//		'\\' c      matches character c
+//		lo '-' hi   matches character c for lo <= c <= hi
+//
+// Match requires pattern to match all of name, not just a substring.
+// The only possible returned error is ErrBadPattern, when pattern
+// is malformed.
+//
+func Match(pattern, name string) (matched bool, err error) {
+Pattern:
+	for len(pattern) > 0 {
+		var star bool
+		var chunk string
+		star, chunk, pattern = scanChunk(pattern)
+		if star && chunk == "" {
+			// Trailing * matches rest of string unless it has a /.
+			// return !strings.Contains(name, "/"), nil
+
+			// Return rest of string
+			return true, nil
+		}
+		// Look for match at current position.
+		t, ok, err := matchChunk(chunk, name)
+		// if we're the last chunk, make sure we've exhausted the name
+		// otherwise we'll give a false result even if we could still match
+		// using the star
+		if ok && (len(t) == 0 || len(pattern) > 0) {
+			name = t
+			continue
+		}
+		if err != nil {
+			return false, err
+		}
+		if star {
+			// Look for match skipping i+1 bytes.
+			for i := 0; i < len(name); i++ {
+				t, ok, err := matchChunk(chunk, name[i+1:])
+				if ok {
+					// if we're the last chunk, make sure we exhausted the name
+					if len(pattern) == 0 && len(t) > 0 {
+						continue
+					}
+					name = t
+					continue Pattern
+				}
+				if err != nil {
+					return false, err
+				}
+			}
+		}
+		return false, nil
+	}
+	return len(name) == 0, nil
+}
+
+// scanChunk gets the next segment of pattern, which is a non-star string
+// possibly preceded by a star.
+func scanChunk(pattern string) (star bool, chunk, rest string) {
+	for len(pattern) > 0 && pattern[0] == '*' {
+		pattern = pattern[1:]
+		star = true
+	}
+	inrange := false
+	var i int
+Scan:
+	for i = 0; i < len(pattern); i++ {
+		switch pattern[i] {
+		case '\\':
+			// error check handled in matchChunk: bad pattern.
+			if i+1 < len(pattern) {
+				i++
+			}
+		case '[':
+			inrange = true
+		case ']':
+			inrange = false
+		case '*':
+			if !inrange {
+				break Scan
+			}
+		}
+	}
+	return star, pattern[0:i], pattern[i:]
+}
+
+// matchChunk checks whether chunk matches the beginning of s.
+// If so, it returns the remainder of s (after the match).
+// Chunk is all single-character operators: literals, char classes, and ?.
+func matchChunk(chunk, s string) (rest string, ok bool, err error) {
+	for len(chunk) > 0 {
+		if len(s) == 0 {
+			return
+		}
+		switch chunk[0] {
+		case '[':
+			// character class
+			r, n := utf8.DecodeRuneInString(s)
+			s = s[n:]
+			chunk = chunk[1:]
+			// possibly negated
+			notNegated := true
+			if len(chunk) > 0 && chunk[0] == '^' {
+				notNegated = false
+				chunk = chunk[1:]
+			}
+			// parse all ranges
+			match := false
+			nrange := 0
+			for {
+				if len(chunk) > 0 && chunk[0] == ']' && nrange > 0 {
+					chunk = chunk[1:]
+					break
+				}
+				var lo, hi rune
+				if lo, chunk, err = getEsc(chunk); err != nil {
+					return
+				}
+				hi = lo
+				if chunk[0] == '-' {
+					if hi, chunk, err = getEsc(chunk[1:]); err != nil {
+						return
+					}
+				}
+				if lo <= r && r <= hi {
+					match = true
+				}
+				nrange++
+			}
+			if match != notNegated {
+				return
+			}
+
+		case '?':
+			_, n := utf8.DecodeRuneInString(s)
+			s = s[n:]
+			chunk = chunk[1:]
+
+		case '\\':
+			chunk = chunk[1:]
+			if len(chunk) == 0 {
+				err = ErrBadPattern
+				return
+			}
+			fallthrough
+
+		default:
+			if chunk[0] != s[0] {
+				return
+			}
+			s = s[1:]
+			chunk = chunk[1:]
+		}
+	}
+	return s, true, nil
+}
+
+// getEsc gets a possibly-escaped character from chunk, for a character class.
+func getEsc(chunk string) (r rune, nchunk string, err error) {
+	if len(chunk) == 0 || chunk[0] == '-' || chunk[0] == ']' {
+		err = ErrBadPattern
+		return
+	}
+	if chunk[0] == '\\' {
+		chunk = chunk[1:]
+		if len(chunk) == 0 {
+			err = ErrBadPattern
+			return
+		}
+	}
+	r, n := utf8.DecodeRuneInString(chunk)
+	if r == utf8.RuneError && n == 1 {
+		err = ErrBadPattern
+	}
+	nchunk = chunk[n:]
+	if len(nchunk) == 0 {
+		err = ErrBadPattern
+	}
+	return
+}
diff --git a/vendor/vendor.json b/vendor/vendor.json
index e45986fa1..c57b90f83 100644
--- a/vendor/vendor.json
+++ b/vendor/vendor.json
@@ -476,16 +476,22 @@
 			"revisionTime": "2017-02-10T18:43:46Z"
 		},
 		{
-			"checksumSHA1": "pjMV8mwWcQ0Kk9cbLWweTGiqYPk=",
+			"checksumSHA1": "oX91yMnimWNI17gVk7iQIE0p2pw=",
 			"path": "github.com/drone/envsubst",
-			"revision": "523de92ea410a5756012669fb628fe42a3056b3e",
-			"revisionTime": "2017-03-25T05:49:59Z"
+			"revision": "15e3f9b7e16332eee3bbdff9ef31f95d23c5da2c",
+			"revisionTime": "2018-10-18T14:46:17Z"
 		},
 		{
-			"checksumSHA1": "CVG/vocbXGLbGKRO//TOlicOBkw=",
+			"checksumSHA1": "CCV0ixQVgQNOsnUn8JlxGJ1v8c4=",
 			"path": "github.com/drone/envsubst/parse",
-			"revision": "523de92ea410a5756012669fb628fe42a3056b3e",
-			"revisionTime": "2017-03-25T05:49:59Z"
+			"revision": "15e3f9b7e16332eee3bbdff9ef31f95d23c5da2c",
+			"revisionTime": "2018-10-18T14:46:17Z"
+		},
+		{
+			"checksumSHA1": "k8a4yeccwcAfBwHgj16Da0F9iQE=",
+			"path": "github.com/drone/envsubst/path",
+			"revision": "15e3f9b7e16332eee3bbdff9ef31f95d23c5da2c",
+			"revisionTime": "2018-10-18T14:46:17Z"
 		},
 		{
 			"checksumSHA1": "AT++gcbYW/VQxkmbInFJk1Feg3o=",