Merge branch 'stable-3.1'

* stable-3.1:
  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: Ia014786e2946804f4a662c1e5d5d7ddbb9c977ec
tree: 69c6750d35efcde2856f6fc282ed08c54b1197c8
  1. src/
  2. BUILD
  3. LICENSE