Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 857de0535fcac0b353cc7f3c555060aa5807cfc7
  - Enable external sources for kuberef shellcheck

    Shellcheck is failing on the execution given that it's missing
    the -x argument. This change fixes that problem adding the argument.

    Signed-off-by: Victor Morales <v.morales@samsung.com>
    Change-Id: Idc1795b604f4b88e5e4468b8fd26b961c08455bf

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 4d96464..857de05 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 4d9646457a7893375744efaefc3fe93521c034d9
+Subproject commit 857de0535fcac0b353cc7f3c555060aa5807cfc7