chore(deps): update docker/build-push-action action to v4.2.1 (#12)

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

Author: renovate[bot]

.github/workflows/push.yaml

@@ -34,7 +34,7 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
       - uses: docker/setup-buildx-action@v2
-      - uses: docker/build-push-action@v4.1.1
+      - uses: docker/build-push-action@v4.2.1
         with:
           context: .
           push: ${{ github.event_name != 'pull_request' }}