Update git submodules

* Update docs/submodules/apex from branch 'master'
  - Merge "Adding unittests for build"
  - Adding unittests for build

    - covers build.py
    - covers build_utils.py
    - moved build_utils out of build module, it wasn't possible to import
      build.py while build_utils was in a module

    Change-Id: I42f08a475d9ca219a62c421d4bdd2d1d3c49691a
    Signed-off-by: Dan Radez <dradez@redhat.com>

diff --git a/docs/submodules/apex b/docs/submodules/apex
index 493876c..3aa975e 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit 493876c4933b5eac8a5026bdd79f2a3a4ae7ac20
+Subproject commit 3aa975e7f5b73f9caa4f759926cc8710b3b0fd92