Merge branch 'stable-3.0'

* stable-3.0:
  Upgrade JGit to 5.3.5.201909031855-r
  Upgrade JGit to 5.1.11.201909031202-r
  Upgrade JGit to 4.11.9.201909030838-r
  Upgrade JGit to 4.7.9.201904161809-r
  Upgrade testcontainers to 1.12.2
  Align testcontainers version constant name prefix with core's
  Upgrade bazlets to latest stable-2.16 to build with 2.16.12 API
  Upgrade bazlets to latest stable-2.15 to build with 2.15.17 API

Change-Id: Ia5af9f0e8ffb6ed8c7eaea9b4be3e8f4723cfb37