Update git submodules

* Update docs/submodules/appc.git from branch 'master'
  to d1a56a7bef30e17462ded7bd9e14449985a32db4
  - Test coverage in ConfigResourceNode

    Add >100 lines of coverage and increase from 71% to 99%
    Increase branch coverage to fix Sonar major issue
    Extract repeated strings to constants

    Issue-ID: APPC-1504
    Change-Id: Ib3b1e83d39f02befaede035b84a0ebef96b36cfd
    Signed-off-by: Joss Armstrong <joss.armstrong@ericsson.com>

diff --git a/docs/submodules/appc.git b/docs/submodules/appc.git
index de4fcf5..d1a56a7 160000 (submodule)
--- a/docs/submodules/appc.git
+++ b/docs/submodules/appc.git
@@ -1 +1 @@
-Subproject commit de4fcf5171fcc7713b83722906ca4364d253abe8
+Subproject commit d1a56a7bef30e17462ded7bd9e14449985a32db4