Proto commits in durch/rust-bigtable

These 2 commits are when the Protocol Buffers files have changed:

Commit:d8c72d0
Author:durch

Update proto files and add support for newer Bigtable API methods - Update proto files from googleapis (latest versions) - Add new proto dependencies: types.proto, request_stats.proto, routing.proto, date.proto - Add 5 new API methods: - PingAndWarm: connection keep-alive - GenerateInitialChangeStreamPartitions: change stream setup - ReadChangeStream: CDC streaming for Apache Beam - PrepareQuery: GoogleSQL query preparation - ExecuteQuery: GoogleSQL query execution - Library now supports all 11 Bigtable Data API v2 methods

The documentation is generated from this commit.

Commit:4571da8
Author:Drazen Urch

Upgrade all dependencies, generate code at build, add proto files, upgrade to 2018