Fix bug where action fails if there is nothing to update

Author: hnkb

.github/workflows/sync.yml

@@ -69,6 +69,7 @@ jobs:
 
   trigger-publish:
     needs: [find-new-versions]
+    if: ${{ needs.find-new-versions.outputs.missing-versions != '[]' }}
     runs-on: ubuntu-latest
     permissions:
       actions: write  # Needed to trigger workflows
@@ -89,4 +90,4 @@ jobs:
               "inputs": {
                 "version": "v${{ matrix.version }}"
               }
-            }'
+            }'