Merge branch 'stable-3.3'
* stable-3.3:
Update git submodules
Bazel: Consume bazel-toolchains release from bazel mirror
Align the recommended buildifier version with CI's
crafting-changes: Add some info on Optional/Nullable
Fix typo in event documentation section
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
Fix NPE on trying to send email for user without email address
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: Id555d1b7b63d5cd0a27ff186be2931ff50dd442d
