Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 4d4e506895df33159b85999903124d62550bf183
  - Fix exclude list for Trivy

    xtesting-mts is not available in all Xtesting versions.

    Change-Id: I71568b7db2b216259fc9ac0e276c4aee3f3bdd19
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index d8942f6..4d4e506 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit d8942f6fb6169a3cd830f3f3af2e2908dac2e6af
+Subproject commit 4d4e506895df33159b85999903124d62550bf183