chore(ci)(deps): bump docker/build-push-action from 5 to 6 (#175)

Merge PR #175: docker/build-push-action 5 → 6

CI dependency update with build summary and export features.
Only affects Docker build workflows.

Author: dependabot[bot]

.github/workflows/docker-multiarch.yml

@@ -100,7 +100,7 @@ jobs:
             ubuntu.version=${{ matrix.ubuntu-version }}
 
       - name: Build and push Docker image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           file: docker/Dockerfile.multiarch