chore(deps): update docker/build-push-action action to v6

Author: renovate[bot]

.github/workflows/ci.yml

@@ -98,7 +98,7 @@ jobs:
       # the build, per https://docs.docker.com/build/cache/backends/gha/.
       - name: Build Runtime
         id: image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           platforms: linux/${{ matrix.arch }}