Update git submodules

* Update docs/submodules/appc.git from branch 'master'
  to e21015630eb54bc5fba3d147962ac1d92a1ac1c8
  - Document OJSI-112 vulnerability
    
    Issue-ID: OJSI-112
    Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
    Change-Id: Id28f332ddcdd5c69f5a82758d05c10d19606faff
    
diff --git a/docs/submodules/appc.git b/docs/submodules/appc.git
index 9efc5e6..e210156 160000
--- a/docs/submodules/appc.git
+++ b/docs/submodules/appc.git
@@ -1 +1 @@
-Subproject commit 9efc5e6ea56013249cb7d9746fa0b21916e79549
+Subproject commit e21015630eb54bc5fba3d147962ac1d92a1ac1c8