ci: bump actions/labeler from 3 to 4

Bumps [actions/labeler](https://github.com/actions/labeler) from 3 to 4.
- [Release notes](https://github.com/actions/labeler/releases)
- [Commits](actions/labeler@v3...v4)

---
updated-dependencies:
- dependency-name: actions/labeler
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/labeler.yml

@@ -8,6 +8,6 @@ jobs:
   triage:
     runs-on: ubuntu-18.04
     steps:
-    - uses: actions/labeler@v3
+    - uses: actions/labeler@v4
       with:
         repo-token: "${{ secrets.GH_PAT }}"