T6781: Use action to auto-close PRs (#4158)

.github/workflows/pr-auto-close.yml

@@ -1,17 +1,18 @@
 name: Auto-Close Pull Requests Circinus
 
 on:
-  pull_request:
+  pull_request_target:
+    types:
+      - opened
     branches:
       - circinus
 
 jobs:
-  auto_close_pr:
+  run:
     runs-on: ubuntu-latest
     steps:
-      - name: Close PR
-        run: |
-          set -eux
-          gh pr close ${{ github.event.pull_request.number }} --repo ${{ github.repository }} --comment "Pull requests to this branch are not accepted and have been closed automatically."
-        env:
-          GH_TOKEN: ${{ secrets.PAT }}
+    - uses: superbrothers/close-pull-request@v3
+      with:
+        # Optional. Post a issue comment just before closing a pull request.
+        comment: "Pull requests to this branch are not accepted and have been closed automatically."
+        github_token: ${{ secrets.PAT }}