Compatibility with voila > 0.5

[mgmarino]

After upgrading to voila 0.5.7 (from 0.4.x), I start getting warnings in the console:

Unsatisfied version 6.0.6 of shared singleton module @jupyter-widgets/base (required ^1 || ^2 || ^3 || ^4)
Unsatisfied version 4.2.0 of shared singleton module @jupyterlab/apputils (required ^3.6.7)

which seems to be coming from the currently supported versions:

ipyvuetify/js/package.json

Line 57 in f4cf06c

"@jupyter-widgets/base": "^1 || ^2 || ^3 || ^4",

Note, I haven't seen any issues as of now, so perhaps it is ok to simply bump (also according to the ipywidgets docs): https://ipywidgets.readthedocs.io/en/latest/migration_guides.html#updating-package-json

Thanks!