Bump docker/build-push-action from 5 to 6 (#602)

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 5 to 6.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v5...v6)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/docker.yml

@@ -49,7 +49,7 @@ jobs:
           registry: ghcr.io
           username: ${{ github.repository_owner }}
           password: ${{ secrets.GITHUB_TOKEN }}
-      - uses: docker/build-push-action@v5
+      - uses: docker/build-push-action@v6
         with:
           push: ${{ github.event_name == 'push' }}
           tags: ${{ steps.meta.outputs.tags }}