Update docker/build-push-action action to v6

Author: renovate[bot]

.github/workflows/ci.yml

@@ -58,7 +58,7 @@ jobs:
       # https://github.com/docker/build-push-action
       - name: Build and push Docker image
         id: build-and-push
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           platforms: linux/amd64,linux/arm64