tensorflow-io 0.9.0 release

[yongtang]

Since TensorFlow 2.0.0 has been released:
https://pypi.org/project/tensorflow/#history

We should plan on having 0.9.0 release. This will happen once 0.8.0 is released (in #459).

/cc @dmitrievanthony @terrytangyuan @BryanCutler

[yongtang]

We releases a patch version of 0.7.1 with the help from @vlasenkoalexey 👍 🎉 , which fixes a bigquery issue for 1.14.0:
https://github.com/tensorflow/io/releases/tag/v0.7.1

For 0.9.0 release, all tests pass and the candidate binaries are located:
https://www.dropbox.com/home/Apps/tensorflow-io-nightly/release/2007/wheelhouse

I will do some additional testing, and, if everything is fine, I will tag and release 0.9.0 (before the end of today).

[yongtang]

Tested on Ubuntu 16.04 + 18.04, with python 2.7, 3.5., 3.6, 3.7, all works fine. Below are the binaries:

0f5ed8088cbe90f2f54f36cbbb25ed92318987187e1050996b67f68257f33ed2  tensorflow_io-0.9.0-cp27-cp27m-macosx_10_13_x86_64.whl
9f4d634b4734a03c6b3583a7c0319f75f7896d6ecf1daf621f03cb81b25ea0ff  tensorflow_io-0.9.0-cp27-cp27mu-manylinux2010_x86_64.whl
18a651284c32219464f72a5970c113c65cf663580203b6757e521fe139ef2934  tensorflow_io-0.9.0-cp35-cp35m-macosx_10_13_x86_64.whl
3b7244707d77097f9874cbd83b62039eed12d9651b63138d5cbd6189d39a63fe  tensorflow_io-0.9.0-cp35-cp35m-manylinux2010_x86_64.whl
286df14596287c9cd2e8e257618b117ad87df8d4d1c08ffe9b290a6f9addc2f5  tensorflow_io-0.9.0-cp36-cp36m-macosx_10_13_x86_64.whl
95daf6733c0077c649e9ea5aebef128989c6df335288aed58db493c944ef5097  tensorflow_io-0.9.0-cp36-cp36m-manylinux2010_x86_64.whl
e51bacee0741c44f4b8adf5e7b6c28b08f10cf8402175cd28d6344d95b016f9d  tensorflow_io-0.9.0-cp37-cp37m-manylinux2010_x86_64.whl

0.9.0 is released in https://github.com/tensorflow/io/releases/tag/v0.9.0

👍 🎉 🎆

[yongtang]

Thanks all for the great contributions! 👍 🎉 🎆