Fix promote job: use explicit paths in metalink put step (#403)

Concourse's inputs:detect cannot resolve glob patterns like
compiled-linux-*/* to actual artifact names. Only version-semver
was detected from the version param, so compiled-linux-amd64 and
compiled-windows-amd64 task outputs were not mounted into the
resource container. filepath.Glob() in the metalink resource's out
script found zero files, producing a metalink with no <file> nodes,
causing: 'bad metalink: content error: missing file node'.

Replace globs with explicit directory names in the files param so
inputs:detect can resolve them correctly.

Author: julian-hj

ci/pipeline.yml

@@ -641,6 +641,6 @@ jobs:
       - put: bosh-agent-index
         params:
           files:
-            - compiled-linux-*/*
-            - compiled-windows-*/*
+            - compiled-linux-amd64/*
+            - compiled-windows-amd64/*
           version: version-semver/number