Update git submodules

* Update docs/submodules/usecase-ui.git from branch 'master'
  to e31a1c4a8e25dbcc12348e210cee3c292547b90d
  - Service instance lifecycle management
    
    Change-Id: Ifd0768dae0d13a8daca99c488323ef1e5751020a
    Issue-ID: USECASEUI-218
    Signed-off-by: guochuyicmri <guochuyi@chinamobile.com>
    
1 file changed