Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "[barometer] Add stable/gambia branch"
  - [barometer] Add stable/gambia branch

    Change-Id: Icc8c518bda5240d814be9110b5d09b19c5868078
    Signed-off-by: Emma Foley <emma.l.foley@intel.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index e973fb9..d12196b 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit e973fb9f04a8f0d61e2a1e761cb30f966b94538e
+Subproject commit d12196be07fde57cd4abf5acda76e6b8246fe007