text: Title: Voila and jupyterlab-github
  Body: I tried to use voila with [jupyterlab-github](https://github.com/jupyterlab/jupyterlab-github) but it doesn't work.
  
  The problem is that voila want to save the notebook before render it, but it is not possible in this case (the files are in readonly mode)
  
  Do you think that it is possible to render the notebook without saving in this case ?
  
  Regards
  