Update git submodules

* Update docs/submodules/pharos from branch 'stable/euphrates'
  - Add fuel installer adapter

    v3 -> v4:
    - extract common variable refs, fold some reusable code;
    - provide dummy defaults for PDFs without net_config;
    - keep yamllint happy about spaces and empty lines;

    v4 -> v5:
    - more folding, define a macro for multiple IP address definition;

    v5 -> v6:
    - added MaaS network / DHCP range support;

    v6 -> v7:
    - removed macro, template code reverted to output style

    JIRA: FUEL-275

    Change-Id: Ib1cc319534d06c088b1db16a43aef663a8ada0d8
    Signed-off-by: Guillermo Herrero <guillermo.herrero@enea.com>
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
    (cherry picked from commit 25b2adb887b5e1cab767023476dd0ec2f02b4b59)

diff --git a/docs/submodules/pharos b/docs/submodules/pharos
index 54875e1..3a8defe 160000 (submodule)
--- a/docs/submodules/pharos
+++ b/docs/submodules/pharos
@@ -1 +1 @@
-Subproject commit 54875e1d0738ee0d717e9f96f3726f20dc210e7b
+Subproject commit 3a8defe6ca168b2a7739ff4fb64543da10f2b3e7