prefer-buildx-build-over-docker-build

Detects CI jobs that run legacy docker build instead of docker buildx build.

This rule looks for:

• docker build ...

and skips:

• docker buildx build ...
• docker buildx bake ...
• docker/build-push-action

Why it matters:

• buildx uses BuildKit.
• BuildKit gives Docker builds better parallelism, cache features, build-and-push flows, and multi-architecture support.
• In many CI paths, switching from docker build to docker buildx build is a low-effort build speed improvement.

What to do:

• Replace docker build with docker buildx build when output behavior can stay equivalent.
• Use --push, --load, or --output intentionally, because buildx output defaults differ from legacy Docker build.
• After switching, consider BuildKit cache mounts or remote cache for expensive build steps.