Update git submodules

* Update docs/submodules/releng from branch 'master'
  to f09100191946bda6bb663a251f3a752fd7880608
  - Remove sig_node_serial from Functest K8s test case list

    Change-Id: I9a3bed680035db90da2ccb52fe307cda08fb8c9f
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index f2b5e9b..f091001 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit f2b5e9b5f666774931b6bbcf47badcde274e6933
+Subproject commit f09100191946bda6bb663a251f3a752fd7880608