Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Generate functest-kubernetes.yaml from playbook

    It takes into account the update of Alpine (3.9).

    Change-Id: I0914986c478daa2e1e0724a8397972964ff00359
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 7c5ec61..c22c5cf 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 7c5ec611f2190ab402449bc2a2049d6bde4263c8
+Subproject commit c22c5cfc963812d813d88ae0f0f4027cc0ce95ad