build(deps): bump docker/metadata-action from 4.4.0 to 4.6.0

Bumps [docker/metadata-action](https://github.com/docker/metadata-action) from 4.4.0 to 4.6.0.
- [Release notes](https://github.com/docker/metadata-action/releases)
- [Commits](c4ee3adeed...818d4b7b91)

---
updated-dependencies:
- dependency-name: docker/metadata-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/publish.yml

@@ -36,7 +36,7 @@ jobs:
 
       - name: Extract metadata (tags, labels) for Docker
         id: meta
-        uses: docker/metadata-action@c4ee3adeed93b1fa6a762f209fb01608c1a22f1e
+        uses: docker/metadata-action@818d4b7b91585d195f67373fd9cb0332e31a7175
         with:
           images: |
             ${{ secrets.DOCKERHUB_USERNAME }}/hullcss