Update git submodules

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

    Change-Id: I3ff145fa0f500182744fd310bb844e4bc5854663
    Signed-off-by: Tim Rozet <trozet@redhat.com>

diff --git a/docs/submodules/apex b/docs/submodules/apex
index ea691fe..54b8b2a 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit ea691fed3042f42701cb355ce1db305564ba229a
+Subproject commit 54b8b2a51e4156d42005158f003fb307b32e45c1