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>

diff --git a/docs/submodules/pharos b/docs/submodules/pharos
index 7cbe4e7..34f15a0 160000 (submodule)
--- a/docs/submodules/pharos
+++ b/docs/submodules/pharos
@@ -1 +1 @@
-Subproject commit 7cbe4e7447280d39fdb5a56b3d9a0fea437b5b15
+Subproject commit 34f15a071a9df12986654593193235a21a774fc8