Update git submodules

* Update docs/submodules/usecase-ui.git from branch 'master'
  to c176eb964eb4877adb35a502791a13434bd57c76
  - style: optimize the style of the home page
    
    Change-Id: I963cdb61aebcb4d049cfc4cc19c5d5dc3b743986
    Issue-ID: USECASEUI-307
    Signed-off-by: cyuamber <xuranyjy@chinamobile.com>
    
1 file changed