Update git submodules

* Update docs/submodules/apex from branch 'stable/euphrates'
  - Use the right branch for apex forks with euphrates

    Change-Id: Iee95bfbf4ac4beb4057403422de8e48a047d33ca
    Signed-off-by: Tim Rozet <trozet@redhat.com>

diff --git a/docs/submodules/apex b/docs/submodules/apex
index ec03e76..7e06254 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit ec03e76b54e69af8daabc9d2b1c30145052ded17
+Subproject commit 7e062540b6865c0751d6e982b496acc0bbc8b6b7