Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Rename files under jjb from 'yml' to 'yaml'

    global-jjb only supports the .yaml file ending for jjb jobs. Instead of
    waiting for a release we're going to rename the files.

    Change-Id: Icf3339eacd2320c583333e02250998cf6b1881f7
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 7bf9e57..afff1f8 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 7bf9e576ff0fffdac04b5892e0e41b63c0735d4e
+Subproject commit afff1f88a918215eeb9060c4f43c5a332c8eb32c