Bump mheap/github-action-required-labels from 3 to 4 (#3610)

Bumps [mheap/github-action-required-labels](https://github.com/mheap/github-action-required-labels) from 3 to 4.
- [Release notes](https://github.com/mheap/github-action-required-labels/releases)
- [Commits](https://github.com/mheap/github-action-required-labels/compare/v3...v4)

---
updated-dependencies:
- dependency-name: mheap/github-action-required-labels
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/block_merge.yml

@@ -6,7 +6,7 @@ jobs:
   block_merge:
     runs-on: ubuntu-latest
     steps:
-      - uses: mheap/github-action-required-labels@v3
+      - uses: mheap/github-action-required-labels@v4
         with:
           mode: exactly
           count: 0