Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 1f0a47d255558da2432d1443790d2d544af2d2be
  - Fix release patttern

    Anuket forces the use of upstream releases (v1.21).

    Change-Id: Ic8b9b57a8a05e2d35c5b46db0a99b45755af8029
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 2a47107..1f0a47d 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 2a47107b3e6c4af001c93e8eda93977b842ddf26
+Subproject commit 1f0a47d255558da2432d1443790d2d544af2d2be