Upgrade Yarn away from v1

[infomiho]

Here are some benefits listed by the project itself: https://yarnpkg.com/migration/overview#why-should-you-migrate

What I have observed: it's a bit confusing to know you need to use the Yarn Classic version vs. the Yarn included in the corepack.

I've used the project successfully with the new version. There was a .yarn folder created which should be committed.

Implementation

The upgrade process should happen automatically, when running yarn install with the newest version. There is some updating needed like removing the export in front the env variables in package.json scripts, but that's pretty much it.