Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Use old functest container for armband CI runs"
  - Use old functest container for armband CI runs

    Functest Alpine not supported yet for aarch64 architecture.
    Task for Armband project but until support could be done, the
    traditionnal docker shall be used for armband tests

    usage of alpine leads to errors [1]

    [1]: https://build.opnfv.org/ci/view/functest/job/functest-fuel-armband-baremetal-daily-master/214/console

    Change-Id: I48e05a0c7cd97989784fd97348bd331425c4877e
    Signed-off-by: Morgan Richomme <morgan.richomme@orange.com>