Update git submodules

* Update docs/submodules/releng from branch 'master'
  to c278e14d818ab6fc6f4e6b7c73d1abaf0a486410
  - Create stable branch jobs for opnfvdocs

    Signed-off-by: Sofia Wallin <sofia.wallin@est.tech>
    Change-Id: I95a516bc740c0259f8b63d6e45f44cd23ea76e54

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 96cd687..c278e14 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 96cd6876d08b1e6293ce42040bdcfef352277704
+Subproject commit c278e14d818ab6fc6f4e6b7c73d1abaf0a486410