Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "container4nfv: trigger yardstick test"
  - container4nfv: trigger yardstick test

    Change-Id: Ifdd504ff199c73a17cf007903a5480ee55f86102
    Signed-off-by: Yibo Cai <yibo.cai@arm.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 91fdca4..9486790 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 91fdca46210a711efd88fc8ebbf0fd1f65ea90c5
+Subproject commit 948679062e550b501d0a04cce9aaab24d11a7112