Update git submodules

* Update docs/submodules/apex from branch 'stable/euphrates'
  - Fixes wrong argument for inventory with clean

    Change-Id: I3ff145fa0f500182744fd310bb844e4bc5854663
    Signed-off-by: Tim Rozet <trozet@redhat.com>
    (cherry picked from commit 54b8b2a51e4156d42005158f003fb307b32e45c1)

diff --git a/docs/submodules/apex b/docs/submodules/apex
index cbc3383..1768744 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit cbc3383820af559b1b69d14968916dd9f074c398
+Subproject commit 1768744b3adf8af0d317ee7d9d16d232f5c59d1f