Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 3cd4d944164408fa42b7b8a438b9cae2140a8c26
  - Rewrite artifact-cleanup jobs

    Change-Id: I7f8766ed3d8fef0e1ab781a065d55f9a133f2fee
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 92324d1..3cd4d94 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 92324d11228d89a7b2020158489422619aed05e4
+Subproject commit 3cd4d944164408fa42b7b8a438b9cae2140a8c26