Release 8.1.1

What's Changed

Bug fixed

• Raise error when copy method is used on base widget class by @mmc1718 in #3780
• Reverts #3689 and #3738 back to the original working codebase by @martinRenou in #3830

Docs

• Update to JupyterLite 0.1.0 by @jtpio in #3820

New Contributors

• @mmc1718 made their first contribution in #3780

Full Changelog: 8.1.0...8.1.1