tensorflow-io 0.9.1 release

[vlasenkoalexey]

I'd like patch 0.9.0 release with #626
Please let me know if you would also like to cherrypick any other fixes.

[tomgross]

On pypi the Python 3.7 wheel for mac is missing. Can you please provide this with 0.9.1?
Thanks!

[vlasenkoalexey]

Normally we don't build mac packages for Python 3.7, but since I had to build everything manually and have setup working I can upload it as an exception. @yongtang FYI, I tested that it works fine, feel free to remove it if you think that we shouldn't provide packages for 3.7 for some reason.

[yongtang]

Thanks @vlasenkoalexey! Python 3.7 for 0.9.1 makes sense as maOS's Catalina have 3.7.3 installed with xcode.

In the next version, we will be able to build python 3.7 with macOS as well I think.