Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Set Functest MultiJob as arch independent"
  - Set Functest MultiJob as arch independent

    Now only one multijob is required to build all containers.
    arm64 containers are still built on opnfv-build-ubuntu-arm.

    functest-vnf and functest-restapi cannot be built due to a segfault
    in ruby operations.

    Change-Id: Iea787e2f4731989f610ba9e596a3f596b750548b
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>