gha: update to actions/labeler@v5

To address warning message:
> Node.js 16 actions are deprecated. Please update the following actions
to use Node.js 20: actions/labeler@v4.

(cherry picked from commit d7f2c13)

.github/workflows/pr-labeler.yml

@@ -11,6 +11,6 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/labeler@v4
+    - uses: actions/labeler@v5
       with:
         repo-token: ${{ secrets.GITHUB_TOKEN }}