Update git submodules

* Update docs/submodules/apex from branch 'stable/gambia'
  - Change OPNFV Artifacts URL

    This change allows downloading of files larger than 20GB.

    Change-Id: I881ea35316e67980d4144e46bfbd41501e80f497
    Signed-off-by: Tim Rozet <trozet@redhat.com>
    (cherry picked from commit 498356c9efb765a5714845ce8303dc8a264eb300)

diff --git a/docs/submodules/apex b/docs/submodules/apex
index 8a62fa4..737708b 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit 8a62fa436cac07cda2cac228d7df54893045d91f
+Subproject commit 737708b6e4a3dd6d897c2d8af3459bab060d30c2