- Revert to 4.1.8 until the ecosystem is ready (notebook)

- Update to 4.2.0
* WorkspacesUI
* Recently opened/closed files
* Full notebook windowing mode by default
* Improved Shortcuts Editor
* Dark high contrast theme
* Keyboard shortcuts improvements
## Bugs fixed
* Check the command is registered before calling
notifyCommandChanged() #16273 (@jtpio)
* Set aria-label to title if no label for #16262 (@fcollonval)
* Fix changing font size in text editor #16261 (@FoSuCloud)
* Fix replace when replacement text matches source text multiple
times #16258 (@JasonWeill)
* Add reopen closed command to tab context menu #16250
(@krassowski)
- Drop some directives working around the former whl install scheme

- Build from source not whl from pypi.