ci: update publish.yml

Author: computationalcore

.github/workflows/publish.yml

@@ -12,7 +12,7 @@ permissions:
 
 jobs:
   publish:
-    if: github.event.workflow_run.conclusion == 'success'
+    if: github.event.workflow_run.conclusion == 'success' && github.ref == 'refs/heads/main'
     runs-on: ubuntu-latest
 
     steps: