Merge pull request #975 from phpDocumentor/backport/1.x/pr-974

[1.x] Merge pull request #974 from phpDocumentor/task/backport

Author: phpdoc-bot

.github/workflows/backport.yaml

@@ -11,6 +11,7 @@ jobs:
     steps:
       - name: "Backport Action"
         uses: "sorenlouv/backport-github-action@v9.3.1"
+        if: "${{ github.event.pull_request.merged == true }}"
         with:
           github_token: "${{ secrets.GITHUB_TOKEN }}"
           auto_backport_label_prefix: "auto-backport-to-"