Merge branch 'stable-3.0' into stable-3.1

* stable-3.0:
  Upgrade bazlets to latest stable-2.16 to build with 2.16.18 API
  Bump Bazel version to 3.1.0

Change-Id: I274b76d6f5830f702cfc9bbcf41c5ca17c24c361
tree: b79551432d996c92c5a0013464c6997d444bbcc1
  1. src/
  2. BUILD
  3. LICENSE