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
    
1 file changed