Update git submodules

Update git submodules

* Update docs/submodules/pharos from branch 'master'
  - Mount PostgreSQL Data from Persistent Volume

    Each time the postgresql container is torn down the database is lost.
    By using a presistent volume managed outside of docker compose, the
    postgresql data can persist across updates and service restarts.

    The volume needs to exist before the postgres container can start: this
    is done with the 'make data' command.

    Note: postgres container creates a volume at /var/lib/postgresql/data.
    Mounting at this location ensures the data is persisted into the
    external volume.

    Change-Id: I958ba57fc735c594378d575bc7108bee0d30c1e3
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>