Merge branch 'stable-2.16' into stable-3.0

* stable-2.16:
  Set version to 2.16.29-SNAPSHOT
  Set version to 2.16.28
  Use JGit 5.1.15.202012011955-r javadoc to resume release build

Change-Id: I9830711780edf9140ef8cd3be2c995074de1df4d