Merge branch 'stable-3.1' into stable-3.2
* stable-3.1:
Bazel: Consume bazel-toolchains release from bazel mirror
Align the recommended buildifier version with CI's
crafting-changes: Add some info on Optional/Nullable
Bump bazel-toolchains to 5.0.0
Set version to 2.16.28-SNAPSHOT
Set version to 2.16.27
ForRef#check should permit internal users to read all refs
Update git submodules
Update highlightjs to 10.6.0
Use NoteDb sequence seed for groups sequence initialization
GroupsOnInit: Remove unused dependency on ReviewDb
Use NoteDb sequence seed for accounts sequence initialization
Do not use ReviewDb anymore when is disabled
Elasticsearch: Discontinue EOL versions 7.2 and 7.3 support
e2e-tests: Add SubmitChangeInBranch scenario
Update developers based on gerritcodereview's list
ForRef#check should permit internal users to read all refs
Change-Id: I72f7184e0de6ed8225c135ec21c8a83c9d211009
