Downgrade labeler to v4 due to actions/labeler#710. (#2598)

Author: Rot127

.github/workflows/labeler.yml

@@ -14,7 +14,7 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-22.04
     steps:
-    - uses: actions/labeler@v5
+    - uses: actions/labeler@v4
       with:
         repo-token: "${{ secrets.GITHUB_TOKEN }}"