Update docker/build-push-action action to v7

Author: renovate[bot]

.github/workflows/docker.yml

@@ -36,7 +36,7 @@ jobs:
           registry: ghcr.io
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
-      - uses: docker/build-push-action@v6
+      - uses: docker/build-push-action@v7
         with:
           context: .
           push: ${{ github.event_name != 'pull_request' }}