Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Fix Yamllint violations for jjb/sfc"
  - Fix Yamllint violations for jjb/sfc

    JIRA: RELENG-254

    Change-Id: I3f878f50de8e0e60d3332ab8cd0ef8224524d38e
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 726be1a..a3d6c79 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 726be1ad6af287564afb6883002cf161a9e432fe
+Subproject commit a3d6c7940218d0bb57840deb26d34959851e4e37