Grpc-go: Breaking change in non-major release

[gbbr]

You have removed the naming package. A deprecated package (or method, function, type for that matter) means that it will be removed in _the next major version_, which means v2.0.0.

This in turn breaks google.golang.org/api which uses it. Now, it is no longer possible to use the latest grpc release along side this package.

Would you consider adding it back in a patch release? With this change you have technically broken semver.

[dfawley]

Please see our published versioning policy. The package was clearly marked as experimental at GA, so it could be removed according to the policy.