Merge pull request containerd#3937 from containerd/dependabot/github_actions/docker/build-push-action-6.15.0

build(deps): bump docker/build-push-action from 6.14.0 to 6.15.0

Author: AkihiroSuda

.github/workflows/ghcr-image-build-and-publish.yml

@@ -60,7 +60,7 @@ jobs:
       # Build and push Docker image with Buildx (don't push on PR)
       # https://github.com/docker/build-push-action
       - name: Build and push Docker image
-        uses: docker/build-push-action@0adf9959216b96bec444f325f1e493d4aa344497  # v6.14.0
+        uses: docker/build-push-action@471d1dc4e07e5cdedd4c2171150001c434f0b7a4  # v6.15.0
         with:
           context: .
           platforms: linux/amd64,linux/arm64