Update git submodules

* Update docs/submodules/apex from branch 'stable/danube'
  - Updates quagga to newer version

    Change-Id: I635b171c15bca40788eefe909eaab3e9d4606db1
    Signed-off-by: Tim Rozet <trozet@redhat.com>
    (cherry picked from commit a9dd0037f9e0d02e83c6f3f6fecb1c706c994878)

diff --git a/docs/submodules/apex b/docs/submodules/apex
index a32ab67..762ccea 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit a32ab67813d8e33c359a5205d221e71ca9409091
+Subproject commit 762ccea54e63eb710491a6da56f5eb3aaa8b8120