Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 6cb4423baf4e254f7dd0b84d44a027a72cfb9583
  - Fix git url

    Change-Id: I14fbf2ee6a9c828c35dcbb650a2e9e676b86fbaa
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index b828378..6cb4423 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit b828378bf58a68708994d9fe1d36d80c633e1a65
+Subproject commit 6cb4423baf4e254f7dd0b84d44a027a72cfb9583