Update git submodules

* Update docs/submodules/sdc.git from branch 'master'
  to 8e039ab3f81af2d1452f1b2db06588883529a428
  - Add tests for the presence of Optional values
    
    Issue-ID: SDC-3012
    Signed-off-by: Chris Andre <chris.andre@yoppworks.com>
    Change-Id: I56cbf7fb5bd04ad2fbc496231d6abe72066124fe
    
diff --git a/docs/submodules/sdc.git b/docs/submodules/sdc.git
index efec7c5..8e039ab 160000
--- a/docs/submodules/sdc.git
+++ b/docs/submodules/sdc.git
@@ -1 +1 @@
-Subproject commit efec7c5f7abb24da6d8ab93a71ee725e1c1f438f
+Subproject commit 8e039ab3f81af2d1452f1b2db06588883529a428