Merge branch 'stable-3.0'

* stable-3.0:
  Upgrade JGit to 4.11.8.201904181247-r
  Upgrade bazlets to latest stable-2.16 to build with 2.16.9 API
  Upgrade bazlets to latest stable-2.15
  Upgrade bazlets to latest stable-2.14
  Upgrade bazlets to latest stable-2.15 to build with 2.15.14 API

Change-Id: I4a31bb18d7569b3951a74d6eab2cdda3364ba68a