github-actions(deps): bump docker/build-push-action from 5 to 6

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
...

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

.github/workflows/docs.yml

@@ -49,7 +49,7 @@ jobs:
           password: "${{ secrets.GITHUB_TOKEN }}"
 
       - name: "Build and push"
-        uses: "docker/build-push-action@v5"
+        uses: "docker/build-push-action@v6"
         with:
           context: "build/docs"
           push: true