Jupyterlab-autosave-on-focus-change

- ✨ Support JupyterLab 4 🍻 (35)

- 🚧 Drop python 3.6 support (19)
- ⬆️🛡️ Upgrade dependencies and requirements to jupyterlab 3.1 (18)
- ⬆️🛡️ Update dependencies (17)

- Fixed bug when saving widget while closing (no more error Popup)
- Filtering cells is more robust

- Fixed bug that saved notebooks on cell focus change
- Added feature to save notebooks on cell focus change

- First release on PyPI.