Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 4d9646457a7893375744efaefc3fe93521c034d9
  - Using default scm macro for kuberef verify jobs

    Switching to a predefined macro for gerrit-git-scm in kuberef verify
    jobs.

    Signed-off-by: Georg Kunz <georg.kunz@est.tech>
    Change-Id: I7e4114fa5b3e9eec9250310a1633c90babac8299

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 4dde8d9..4d96464 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 4dde8d957248be0cc77abfa0af770762cee6960a
+Subproject commit 4d9646457a7893375744efaefc3fe93521c034d9