upgrade envsubst

vendor/github.com/drone/envsubst/README

@@ -1,8 +1,8 @@
-Go package emulates bash environment variable substitution in a string using ${var} syntax. Includes support for bash string replacement functions.
+Go package for expanding variables in a string using ${var} syntax. Includes support for bash string replacement functions.
 
 Documentation:
 
-    http://godoc.org/github.com/drone/env
+    http://godoc.org/github.com/drone/envsubst
 
 Supported Functions:
 

vendor/github.com/drone/envsubst/funcs.go

@@ -1,6 +1,7 @@
 package envsubst
 
 import (
+	"path"
 	"strconv"
 	"strings"
 	"unicode"
@@ -150,28 +151,77 @@ func replaceSuffix(s string, args ...string) string {
 
 func trimShortestPrefix(s string, args ...string) string {
 	if len(args) != 0 {
-		s = strings.TrimPrefix(s, args[0])
+		s = trimShortest(s, args[0])
 	}
 	return s
 }
 
 func trimShortestSuffix(s string, args ...string) string {
 	if len(args) != 0 {
-		s = strings.TrimSuffix(s, args[0])
+		r := reverse(s)
+		rarg := reverse(args[0])
+		s = reverse(trimShortest(r, rarg))
 	}
 	return s
 }
 
 func trimLongestPrefix(s string, args ...string) string {
 	if len(args) != 0 {
-		s = strings.TrimPrefix(s, args[0])
+		s = trimLongest(s, args[0])
 	}
 	return s
 }
 
 func trimLongestSuffix(s string, args ...string) string {
 	if len(args) != 0 {
-		s = strings.TrimSuffix(s, args[0])
+		r := reverse(s)
+		rarg := reverse(args[0])
+		s = reverse(trimLongest(r, rarg))
 	}
 	return s
 }
+
+func trimShortest(s, arg string) string {
+	var shortestMatch string
+	for i :=0 ; i < len(s); i++ {
+		match, err := path.Match(arg, s[0:len(s)-i])
+
+		if err != nil {
+			return s
+		}
+
+		if match {
+			shortestMatch = s[0:len(s)-i]
+		}
+	}
+
+	if shortestMatch != "" {
+		return strings.TrimPrefix(s, shortestMatch)
+	}
+
+	return s
+}
+
+func trimLongest(s, arg string) string {
+	for i :=0 ; i < len(s); i++ {
+		match, err := path.Match(arg, s[0:len(s)-i])
+
+		if err != nil {
+			return s
+		}
+
+		if match {
+			return strings.TrimPrefix(s, s[0:len(s)-i])
+		}
+	}
+
+	return s
+}
+
+func reverse(s string) string {
+	r := []rune(s)
+	for i, j := 0, len(r)-1; i < len(r)/2; i, j = i+1, j-1 {
+		r[i], r[j] = r[j], r[i]
+	}
+	return string(r)
+}

vendor/github.com/drone/envsubst/parse/parse.go

@@ -30,7 +30,7 @@ func (t *Tree) Parse(buf string) (tree *Tree, err error) {
 
 func (t *Tree) parseAny() (Node, error) {
 	t.scanner.accept = acceptRune
-	t.scanner.mode = scanIdent | scanLbrack
+	t.scanner.mode = scanIdent | scanLbrack | scanEscape
 
 	switch t.scanner.scan() {
 	case tokenIdent:

vendor/github.com/drone/envsubst/parse/scan.go

@@ -181,6 +181,11 @@ func (s *scanner) scanEscaped(r rune) bool {
 	if s.mode&scanEscape == 0 {
 		return false
 	}
+	if r == '$' {
+		if s.peek() == '$' {
+			return true
+		}
+	}
 	if r != '\\' {
 		return false
 	}

vendor/vendor.json

@@ -285,16 +285,16 @@
 			"revisionTime": "2017-02-10T18:43:46Z"
 		},
 		{
-			"checksumSHA1": "7tosn2Sxlubl+7ElXSZ6Mz8tAjY=",
+			"checksumSHA1": "pjMV8mwWcQ0Kk9cbLWweTGiqYPk=",
 			"path": "github.com/drone/envsubst",
-			"revision": "3e65ae5fd2d944d56fdf52cb3f887247498d50e9",
+			"revision": "523de92ea410a5756012669fb628fe42a3056b3e",
-			"revisionTime": "2017-01-18T15:01:55Z"
+			"revisionTime": "2017-03-25T05:49:59Z"
 		},
 		{
-			"checksumSHA1": "LPKfsjm4AYVgCLVcAWnQdSpt5SA=",
+			"checksumSHA1": "CVG/vocbXGLbGKRO//TOlicOBkw=",
 			"path": "github.com/drone/envsubst/parse",
-			"revision": "3e65ae5fd2d944d56fdf52cb3f887247498d50e9",
+			"revision": "523de92ea410a5756012669fb628fe42a3056b3e",
-			"revisionTime": "2017-01-18T15:01:55Z"
+			"revisionTime": "2017-03-25T05:49:59Z"
 		},
 		{
 			"checksumSHA1": "++oBqqmh8bt50iB6/I+BHnrzC80=",