Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Hardcode Jenkins Credential ID for Git Clones"
  - Hardcode Jenkins Credential ID for Git Clones

    Though these aren't needed, as almost all clones are over HTTPs, jobs
    still complain the SSH_CREDENTIAL_ID is not set. Instead of updating all
    use of 'git-scm', and 'ssh-agent-wrapper', these are hard coded for now.

    Change-Id: If4402ac570f6dd412938d392c20ad434c818dc9a
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>