Update git submodules

* Update docs/submodules/apex from branch 'stable/danube'
  - Fixing BGPD service is not running

    Change-Id: Ia94a82cda8cd2c8c052bfd3454e3753b6eb54288
    Signed-off-by: Nikolas Hermanns <nikolas.hermanns@ericsson.com>
    (cherry picked from commit 16d8540f09d494f86db448b91aa47cfad126af03)

diff --git a/docs/submodules/apex b/docs/submodules/apex
index d7cd79b..aaa6cad 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit d7cd79b099f71d5f1d46498222d9bb0c7cbdcc6a
+Subproject commit aaa6cad0c1247d5f062bedaedc8df438fc02f746