* chore(ci): CI scripts cleanup, add Node 14 and 15 runs, bump checkout action
* chore(ci): attempt to fix Yarn v2 install
* chore(ci): another attempt to fix Yarn v2 install
* use local yarn-deduplicate
* move yarn config steps earlier
* remove localhost registry config
* revert changes, temporary remove lock update from postinstall
* revert to use Yarn v2 only for website build
* revert back localhost registry
* missing flag
* is it node 15 to blame?
* not running yarn v2 on workspace so lock update can be reverted
* chore(v2): Add E2E test for yarn v2
* Remove root node_modules to prevent them from accessible in e2e test
The purpose of e2e test is to ensure that the docusaurus inited website can stand on its own. The root node_modules remain accessible according to how node resolution works and it might interfere with the test. Remove them for safety.
* Add @mdx-js/react to docusaurus init templates
Bartosz Kaszubowski