Update git submodules

* Update freezer-web-ui from branch 'master'
  - Cleanup py27 support
    
    Make a few cleanups:
    - Remove python 2.7 stanza from setup.py
    - Add requires on python >= 3.6 to setup.cfg so that pypi and pip
      know about the requirement
    - Remove obsolete sections from setup.cfg:
      * Wheel is not needed for python 3 only repo
      * Some other sections are obsolete
    - Update classifiers
    - Update requirements, no need for python_version anymore
    - Remove unused oslosphinx requirement
    
    Change-Id: I845d02c5fb7cf57beb3628821156bff7310733ca