Use yarn 3

[fisker]

Description

Checklist

• I’ve added tests to confirm my change works.
• (If changing the API or CLI) I’ve documented the changes I’ve made (in the docs/ directory).
• (If the change is user-facing) I’ve added my changes to changelog_unreleased/*/XXXX.md file following changelog_unreleased/TEMPLATE.md.
• I’ve read the contributing guidelines.

✨Try the playground for this PR✨

[kachkaev]

The diff makes sense!

I’m using Yarn 3 in a few side projects – it works quite well with nodeLinker: node-modules. PnP support is still a bit rough, but we don’t need to use it right away.

Here is an example of a two-step migration from Yarn 1 to Yarn 3 + PnP, just for comparison:

• Upgrade from Yarn v1 to v3 while keeping node_modules kachkaev/njt#160
• Yarn Berry: Switch from from node_modules to PnP  kachkaev/njt#161

Step 1 looks very similar to this PR.

Before we decide to use Yarn 3 in the main branch, we need to make a decision on Dependabot. Unfortunately, it does not support Yarn 3 ATM (dependabot/dependabot-core#1297). We’ll have to wait or switch to Rennovate I guess.

[kachkaev]

Do we need to keep multiple yarn.lock files? Yarn 3 has an improved ‘focus mode’ for workspaces, if I remember correctly. In theory, there can be just one yarn.lock at the top of the repo, but we'll be still able to install dependencies selectively. Maybe I'm wrong though.

[fisker]

Do we need to keep multiple yarn.lock files?

I think we do, we run release script from scripts/release and during the release it removes the one in root and reinstall everything. But I'm not sure.

[fisker]

Before we decide to use Yarn 3 in the main branch

Unfortunately, the CI log is telling us we can't, it seems yarn 3 don't support Node.js 10.

[kachkaev]

Yarn 3 don't support Node.js 10

Yeah, that's a shame. We can probably finish this PR after Prettier v3 is out then. We'll have an opportunity to drop Node 10 and 12 I guess.