Update hmarr/auto-approve-action action to v4 (#35)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/auto-approve.yml

@@ -7,7 +7,7 @@ jobs:
   auto-approve:
     runs-on: ubuntu-22.04
     steps:
-      - uses: hmarr/auto-approve-action@v3.2.1
+      - uses: hmarr/auto-approve-action@v4.0.0
         if: github.actor == 'scala-steward' || github.actor == 'renovate[bot]'
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}