Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Apex: Fix building for gambia

    The logic should have been checking for stable/fraser and didn't account
    for newer branches other than master.

    Change-Id: I1164ce57338ba1734aa68c98bfe22a8a5f4209ac
    Signed-off-by: Tim Rozet <trozet@redhat.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 0a31ec9..e5840dc 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 0a31ec9e8c3dd0e7f99cc7ba4e9201c20a92e28e
+Subproject commit e5840dcb1af4f89450bfbb820cbfdb7520352485