Update git submodules

Update git submodules

* Update docs/submodules/oom.git from branch 'master'
  to 21d5e7be75d5e8aa4abfe269bea89edec38c75c1
  - Merge "[DOC] Add a link to release note"
  - [DOC] Add a link to release note

    New documentation generation system relies on disjoint documentations.
    This patch adds an label for OOM release note with name being consistent
    accross all ONAP components.

    Issue-ID: CIMAN-33
    Change-Id: I5e5fbe5d5038056a7a684828c9e02f082bfa7f0b
    Signed-off-by: lf-jobbuilder <releng+lf-jobbuilder@linuxfoundation.org>
    Signed-off-by: Sylvain Desbureaux <sylvain.desbureaux@orange.com>