Merge branch 'stable-2.15' into stable-2.16

* stable-2.15:
  Upgrade bazlets to latest stable-2.15 to build with 2.15.15 API
  Upgrade testcontainers to 1.12.0

Change-Id: Icc2122a6dd49afcb217af58e3d8e2c7af0c3d6f5