Add support for ipywidgets 8

Packages such as tqdm will not work with the latest version of IPyWidgets 8

• Explore supporting IPyWidgets 8

Work around - Please install ipywidgets==7.7.2

[alex180500]

any update on this?

[DonJayamanne]

Required work to get this working in VS Code:

• Support running kernel startup code prior to synchronizing kernel messages with webview kernel
  • Buffer kernel messages, see work done in lazy creation of controllers (switching controller from remote kernel spec to live kernel spec)
• Support lazy loading of IPyWidget script instead of statitcally contributing this in controller
• Support querying version of ipywidgets
• Create a loader script that will load version 7 or 8 of ipywidgets
  • Careful thought needs to go into designing this (see last point)
• Publish IPyWidget npm package as version 7
  • Plan is to eventually create a seprate branch for v7 after publishing to version 7 (consider this new branch as the branch for maintenance of the older version, hopefully no more changes here)
  • The main branch will subsequently be used for version 8 & the new version of npm will be version 8
• Pull in the npm package version 7 into Jupyter extension
• Review the renderer script, we might need to make some changes there for
  • https://github.com/microsoft/vscode-jupyter/issues/8635
  • For loading existing widget state from notebooks
  • This will probably end up pulling in be the loader script in some form that loads version 7 or version 8 of the widget script