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] <[email protected]>

Author: dependabot[bot]

.github/workflows/docker-release.yaml

@@ -29,7 +29,7 @@ jobs:
             core.setOutput('no-v', no_v)
             core.setOutput('no-dash', no_dash)
       - name: Build and push tag ${{steps.set_version.outputs.no-dash}} for backend
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           file: ./dockerfiles/backend.Dockerfile
@@ -41,7 +41,7 @@ jobs:
             ${{ secrets.DOCKERHUB_USERNAME }}/azure-ai-services-solutions:backend-${{steps.set_version.outputs.no-dash}}
             ${{ secrets.DOCKERHUB_USERNAME }}/azure-ai-services-solutions:backend-latest
       - name: Build and push tag ${{steps.set_version.outputs.no-dash}} for frontend
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           file: ./dockerfiles/frontend.Dockerfile