Update git submodules

* Update docs/submodules/apex from branch 'master'
  - Updates rdo images URL

    The delorean path does not have images for rocky, however they do exist
    under the rdo_trunk path. Comparing the images for queens between the 2
    paths looks the same, so switching to this URL.

    Change-Id: I5d762af69b984c0fed1c79b73f2b4d61341298fa
    Signed-off-by: Tim Rozet <trozet@redhat.com>

diff --git a/docs/submodules/apex b/docs/submodules/apex
index e1c1254..a169531 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit e1c125496077fe9b693c80ad0ab9e345f1d2f438
+Subproject commit a16953172cca0026496ab2002f23e8ed1b709c5d