message: Remove docker build test on macOS (Linux is kept)
  This PR removes docker build test on macOS as
  docker install on GitHub Actions macOS is not very stable
  and often breaks (See e.g., https://github.com/tensorflow/io/runs/1024230016).
  We are still covered with Linux for docker build test.
diff: @@ -213,16 +213,6 @@ jobs:
  set -x -e
  python --version
  bash -x -e .github/workflows/build.wheel.sh python
  - - name: Test docker images on macOS
  - run: |
  - set -x -e
  - mkdir -p ~/.docker/machine/cache
  - curl -Lo ~/.docker/machine/cache/boot2docker.iso https://github.com/boot2docker/boot2docker/releases/download/v19.03.12/boot2docker.iso
  - brew install docker docker-machine
  - docker-machine create --driver virtualbox default
  - docker-machine env default
  - eval "$(docker-machine env default)"
  - bash -x -e tools/docker/tests/dockerfile_cpu_test.sh
  linux-bazel:
  name: Bazel Linux
  