Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 4308d8fb6bdcda958352dd20bbc05f277eb166e5
  - Clean Functest K8s jjb

    It stops producing containers for closed K8s versions.
    https://kubernetes.io/releases/

    Change-Id: I09905178fb42868a367b5077c16b583985ae867b
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index a799f80..4308d8f 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit a799f8028de63f4638b66fc504dc1765dc271fb5
+Subproject commit 4308d8fb6bdcda958352dd20bbc05f277eb166e5