build(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/docker-build-push.yml

@@ -56,7 +56,7 @@ jobs:
 
     - name: 'Build & Push to Docker Hub (Jikkou CLI)'
       if: github.ref_name == 'main'
-      uses: docker/build-push-action@v5
+      uses: docker/build-push-action@v6
       with:
         context: docker
         platforms: linux/amd64,linux/arm64
@@ -72,7 +72,7 @@ jobs:
 
     - name: 'Build & Push to Docker Hub (Jikkou CLI)'
       if: startsWith(github.ref, 'refs/tags/v')
-      uses: docker/build-push-action@v5
+      uses: docker/build-push-action@v6
       with:
         context: docker
         platforms: linux/amd64,linux/arm64