Merge branch 'stable-3.0' into stable-3.1

* stable-3.0:
  Bump Bazel version to 3.7.0
  Upgrade bazlets to latest stable-3.0 to build with 3.0.13 API

Change-Id: I8de8bd2efc74d22b4ceae7425e4bc6e1cb8fad6d