* Rough upgrade

* Fix CI step order

* Fix stylelint

* Update year on licenses

* Fix artifact path

* Import mathjax2

* Create skeleton for integration tests

* Add integration tests

* Fix linter

* Fix CI matrix

* Test against 3.x

* Fix Galata server configuration

* Update mathjax2 snapshots

* Fix integration tests

* Fix cross compatibility

* Propagate cross fix

* Upgrade JupyterLab and Lumino

* Yarn dedupe

* Update sed

* Test using DOM snapshot

* Compare DOM snapshots

* Lint the code

* Fix tests for 3.6

* Try fixing playwright

* Second attempt to fix the ui-tests for 3.6

* Ignore Katex for 3.6
Fix Vega3 selector