Update git submodules

* Update docs/submodules/apex from branch 'stable/euphrates'
  - This config is no longer needed

    it is setting and unescaped default value which ended up setting an
    invalid value. removing it uses the default which accomplishes what
    this was originally attempting to put into place.

    Change-Id: I03660921860adf7625e17d2c4a3ba07b62d0f3f0
    Signed-off-by: Dan Radez <dradez@redhat.com>
    (cherry picked from commit 811bb2c4878973fd3c479d880bb6aea9b1c2958c)

diff --git a/docs/submodules/apex b/docs/submodules/apex
index 6e7af7e..7771d50 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit 6e7af7e195f509a6658d65874ff179568ff8fda4
+Subproject commit 7771d5010b9845576ceb0bbe5ad5f405ed99b871