Merge branch 'stable-3.0'

* stable-3.0:
  Upgrade bazlets to latest stable-3.0 to build with 3.0.4 API
  Upgrade JGit to 5.1.12.201910011832-r
  Upgrade bazlets to latest stable-2.16 to build with 2.16.13 API

Change-Id: Ic4f67778b1f255aa163b292b25c5d01c91111a8f