fix: release-doc only triggered for tags

Author: georgeh0

.github/workflows/release.yml

@@ -129,5 +129,6 @@ jobs:
   release-docs:
     name: Release Docs
     needs: [release]
+    if: ${{ startsWith(github.ref, 'refs/tags/') }}
     uses: ./.github/workflows/_doc_release.yml
     secrets: inherit