Update git submodules

* Update docs/submodules/apex from branch 'stable/danube'
  - Merge "Fix tacker not starting correctly" into stable/danube
  - Fix tacker not starting correctly

    JIRA: APEX-446

    Change-Id: I69fecfa8dae111cc53d83e701ce913de80de94ef
    Signed-off-by: Tim Rozet <trozet@redhat.com>

diff --git a/docs/submodules/apex b/docs/submodules/apex
index adf74f5..742be8f 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit adf74f577852779302ed77b1d45584af9830c1e2
+Subproject commit 742be8f455b9526fd32fc903aedc2608c90ead93