Add token to check-pr

.github/workflows/check-pr.yml

@@ -22,6 +22,7 @@ jobs:
     steps:
     - uses: peter-evans/close-pull@v1
       with:
+        token: ${{ github.token }}
         delete-branch: false
         comment: >
           Thanks for your contribution! Unfortunately we can't accept PRs directed at release branches. We make patches to the bugfix branches and only later do we push them out as releases.