Update git submodules

* Update docs/submodules/apex from branch 'stable/euphrates'
  - Install honeycomb and vpp in a single step

    We currently install Honeycomb and VPP in 2 steps, this could potentially
    cause version conflicts.

    Change-Id: I1e54a576bced07f5115b12fef3bbdf2e95e9ab90
    Signed-off-by: Feng Pan <fpan@redhat.com>
    (cherry picked from commit e915d21073b5b780f9abfc7ab50d6fede6b1d93a)

diff --git a/docs/submodules/apex b/docs/submodules/apex
index 15208f5..43f65e1 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit 15208f52f1c9dbea048cd363e0caae3a8e95d954
+Subproject commit 43f65e19443168ea7ab1d372902318c0129d6306