feature: upgrade to Yarn 2

[hydrosquall]

Yarn 2 was released a year and a half ago, with the RC for Yarn 3 currently underway. The main benefits for me have been improvements to the workspaces feature, and the "zero node modules install" setup (where all your dependencies are zipped and committed into the repo)

https://yarnpkg.com/getting-started/qa#why-should-you-upgrade-to-yarn-modern

Wanted to check if there was interest before exploring whether that would be feasible in this repo.