Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 2039ffda9cced951523b1b8138f7406e2446c717
  - Push Docker Release from Tags on the Master Branch

    Any change that was merged to master for docker builds was tagged as
    latest, regardless if that change was triggered by a new tag. This fixes
    the docker script logic to allow containers to be tagged and pushed from
    tags on the master branch.

    Change-Id: I80e019b90d2dd3dd216005a3bd62d6d741c1d507
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>