gRPC Python dropping support for Beta API 2018-07-01

[Nathaniel Manista]

(If you don't work with gRPC Python, or if your code does not use code elements in the "grpc.beta" Python package, you can stop reading now.)

Use of gRPC Python's Beta API (code elements in the "grpc.beta" package) has been discouraged since the release of gRPC Python 1.0 on 2016-08-19. We will be dropping support for the Beta API on 2018-07-01 (and removing it from future releases).

Please let us know in the issue tracker if you have any difficulty upgrading to the current gRPC Python API (code elements in the "grpc" Python package).

-N