* stable-2.16:
Update git submodules
CommitValidators: Use ImmutableList.Builder instead of ImmutableList.of
Update git submodules
Update git submodules
Update git submodules
Always verify PolyGerrit if bazel related files are changed
Always run all tests, if bazel-related files are changed
Make cache disk stat metric computation optional
ReceiveCommits: Log "update failed" at severe level
Revert "Insert Change-Id at start of trailers"
Revert "commit-msg: Remove obsolete comments"
Remove obsolete UpgradeFrom2_0_x init step
Update git submodules
Update git submodules
Improve documentation of change refs
Change-Id: I18e9bf5dee8943ef8b5e6e176a2cfd9f62acdafa