Merge branch 'stable-2.16' into stable-3.0

* stable-2.16:
  Bump Bazel version to 3.0.0
  Upgrade bazlets to latest stable-2.16 to build with 2.16.17 API
  Upgrade bazlets to latest stable-2.16

Change-Id: Id6eaa7aa62f3d173ce36d7c50cff6249e6ec2117