Update git submodules

Update git submodules

* Update docs/submodules/modeling/modelspec.git from branch 'master'
  to 9e24ecc370062ef3c7a080141bc1028b61006d49
  - Merge "Migrate modeling-modelspec docs"
  - Migrate modeling-modelspec docs

    Merging this will create
    https://onap-modeling-modelspec.readthedocs.io
    This build will run in parallel
    to the current docs generation method
    until we are ready to cut over.

    Issue-ID: CIMAN-364
    Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
    Change-Id: Ia85ec71d6a14b66479293a167b108b27c4f74990