Migrate away from yarn 1/classic

[jagthedrummer]

Migrate away from yarn 1/classic

[jagthedrummer]

@gazayas Looks like we probably want to tweak .gitignore to not ignore quite so much. https://yarnpkg.com/getting-started/qa#which-files-should-be-gitignored

I wonder if version 3.5.1 might have put some kind of version identifier somewhere in .yarn/ to keep track of which version to use.

I'll add the .gitignore tweaks to #1445 tomorrow.

[gazayas]

I've been curious about this for a while, and we temporarily had things working with v3.5.1 back in #754, but I haven't looked at it in a bit. That PR might have some hints though.

[jagthedrummer]

@gazayas that's interesting, and I'd forgotten about that PR. I don't find anything in the contents of that PR that actually pins yarn to a version. So maybe you were just using 3.5.1 locally? And we were still running 1.22.22 in CI?

[gazayas]

@jagthedrummer I don't quite remember the CI setup at that point, but yes, I was running v3.5.1 locally. It created all these files in .yarn/ which I put in .gitignore, but it might be a different setup in v4.

It seems like you got v4 to pass on CI though? I'll see if I can test out the branch locally soon.