Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Add RTD Verify and Merge jobs for Releng"
  - Add RTD Verify and Merge jobs for Releng

    These jobs come from global-jjb[1]. On verify, 'tox -e docs' is ran
    against releng, and on merge at webhook it curl-ed on RTD to build the
    docs.

    The merge job additionally requires jq installed to verify the build was
    triggered.

    [1] https://docs.releng.linuxfoundation.org/projects/global-jjb/en/latest/jjb/lf-rtd-jobs.html

    Change-Id: Ib0d752a904a9fdda2ab13016509a0b82d34ec3ee
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>