Change builder release trigger to module tag (#10429)

This PR changes the trigger for releasing the builder to match the
builder module tag. This allows us to release the builder separately by
pushing a dedicated tag.

.github/workflows/builder-release.yaml

@@ -3,7 +3,7 @@ name: Builder - Release
 on:
   push:
     tags:
-      - 'v*'
+      - 'cmd/builder/v*'
 
 jobs:
   goreleaser: