Update git submodules

* Update docs/submodules/apex from branch 'stable/danube'
  - Fixes relative path for 'ip' command

    Change-Id: I63606f7cc200ddbe35c6df2cbb56fa442c2bfb9b
    Signed-off-by: Tim Rozet <trozet@redhat.com>
    (cherry picked from commit e0eda9d2ce02eb0afddd66f328f8794b073a7958)

diff --git a/docs/submodules/apex b/docs/submodules/apex
index 605342b..b5e4091 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit 605342b46095341c9301456c81e354c73e2197eb
+Subproject commit b5e4091424ced384b49f6ff13b1ef2b63466f947