Remove docker build test on macOS (Linux is kept) (#1102)
Remove docker build test on macOS (Linux is kept) (#1102)

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.

Signed-off-by: Yong Tang <765086fe2e0c1f980161f127fec596800f327f62@outlook.com>
tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io