Merge branch 'stable-3.0' into stable-3.1

* origin/stable-3.0:
  Upgrade bazlets to latest stable-3.0 to build with 3.0.8 API
  Upgrade bazlets to latest stable-3.0
  Upgrade bazlets to latest stable-2.16
  Bump Bazel version to 2.2.0

Change-Id: Id1ffc342dcdbc11c6b301a056396c3ae81b0f32c