Update git submodules

Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Patch Functest docker images for ARM

    A new tox env is defined to ease patching all Dockerfiles for ARM.
    This env will only patch the Dockerfile related to functest-core when
    the manifests are published.

    Jenkins jobs can simply apply the next command:
        $ tox -e patcharm64

    Co-Authored-By: Cédric Ollivier <cedric.ollivier@orange.com>
    Change-Id: Icf69e27c1da95a721ebf67d5ce190c9b8cefce0a
    Signed-off-by: Delia Popescu <delia.popescu@enea.com>
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>