message: Fix CEGUI module URL
diff: url = https://gitlab.com/InnerPieceOSS/cegui_alfisko.git
  [submodule "3rdparty/CEGUI/cegui"]
  path = 3rdparty/CEGUI/cegui
  - url = https://github.com/nothings/stb.git
  + url = https://gitlab.com/InnerPieceOSS/cegui.git
  [submodule "ext/CEGUI/stb"]
  path = ext/CEGUI/stb
  url = https://github.com/nothings/stb.git
  