Merge branch 'stable-3.0' into stable-3.1
* stable-3.0:
Documentation: Fix parentForDeletedProjects in config.md
Bump Bazel version to 2.2.0
Bump required Bazel version to 2.1.0
Upgrade bazlets to latest stable-2.16 to build with 2.16.16 API
Documentation: Refactor to match other plugin documentation
Add an empty tools/BUILD file explicitly for Bazel
Upgrade bazlets to latest stable-2.16
Upgrade bazlets to latest stable-2.16
Upgrade bazlets to latest stable-2.15
Upgrade bazlets to latest stable-2.14
config.md: Correct formatting of config values
Change-Id: Ib60d65a8d278e97e0eb4d98dc115ced9500b7afc