Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Create Stable Branch Jobs for snaps"
  - Create Stable Branch Jobs for snaps

    Change-Id: Id06a66a53d2db7f76e87634adfa2b71ce517a0eb
    Signed-off-by: jenkins-ci <jenkins-opnfv-ci@opnfv.org>
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index e5555b2..f3f5395 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit e5555b2b943ecd5388c0ffa4a2785c9f8732f739
+Subproject commit f3f539589239a4ed38ae427d4062fbd7966608e7