Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Create vnf and restapi images-built job for arm"
  - Create vnf and restapi images-built job for arm

    Change-Id: Ife5d1726680db34d5d027cd592510bdd1123a965
    Signed-off-by: Linda Wang <wangwulin@huawei.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index e47b91a..42f9908 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit e47b91acf5b085fcc87a8b962a36292726e3e516
+Subproject commit 42f9908705ce1699f2645015edc50c5c3d77ab4a