Consider replacing yarn with pnpm

[jmrossy]

Yarn v1 was ahead of the game for a while with it's monorepo support that greatly improved on lerna. However, in the years since then, yarn has generally fallen behind and pnpm is leading the pack.

In particular it has:

1. Better performance
2. Better monorepo features
3. Better security
4. Growing usage
5. Generally better user satisfaction (from what I hear)

[yorhodes]

what about bun

[jmrossy]

@yorhodes bun is very cool, very fast, and also prioritizes security so it's worth considering!
I do have two small reservations though:

1. I wouldn't recommend using the bun package manager unless we also replace our usage of node with bun. Which would be nice but since the majority of our CLI users will use node, risk of missing a node-specific bug is a bit higher
2. I don't know how good bun's monorepo features are. The docs say it supports workspaces, I just don't know personally how good they are and haven't heard anything about it yet.