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: Ice7e6fb0438f2f549803591e46f0c7fe2b94d3c1