Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Output version before Docker builds

    Its helpful to know which version of docker is being used to build a
    project when debugging build failures.

    Change-Id: I2bb9c5386d1d69e61c4477913f5f0162acd0c47d
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index e5424a6..909c05e 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit e5424a6cecf733f17f1cd16596938e3207d6c190
+Subproject commit 909c05e522f04aed90c1f49365c549176be0b680