Update git submodules

* Update docs/submodules/vnfrqts/guidelines.git from branch 'master'
  to 19b4e18248f81c7f468f74ae8de612f10f771f38
  - Update css file name in conf.py
    
    ribbon.css is the correct name of the css file.
    
    Issue-ID: CIMAN-376
    Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
    Change-Id: I18705964e1cd24810c61efc43fcd62d871d46603
    
1 file changed