Update git submodules

Update git submodules

* Update docs/submodules/sdc.git from branch 'master'
  to 031db8630dda9706e22aa3bbdf0f2dfba33fb86e
  - Validate PM Dictionary and VES Events YAML Files

    Validate, during the package onboarding, YAML files declared in the
    manifest as type onap_ves_events or onap_pm_dictionary under
    non_mano_artifact_sets. Check if the file is not empty, if has a yaml
    extension and if it has a valid yaml content.

    Change-Id: I260d0f5355e9e77b6499f553f8aa9f7e6d0693da
    Issue-ID: SDC-2475
    Signed-off-by: andre.schmid <andre.schmid@est.tech>