Rebuild docs for api changes and add deploy preview (#1979)

.woodpecker/docs.yml

@@ -7,6 +7,8 @@ variables:
     # since we generate docs for cli tool we have to watch this too
     - "cli/**"
     - "cmd/cli/**"
+    # api docs
+    - "server/api/**"
 
 steps:
   build-cli:

.woodpecker/web.yml

@@ -6,6 +6,8 @@ variables:
         - ".woodpecker/web.yml"
         # web source code
         - "web/**"
+        # api source code
+        - "server/api/**"
       branch:
         exclude: ${CI_REPO_DEFAULT_BRANCH}
       event: push