build: Yarn Berry Playground

[MaikoTan]

Per #3292

Plug'n'Play

PnP feature is enabled, but there are still errors with mocha and else.

Offline Cache

As yarn suggests, the cache (aka packages from npm) is bundled and uploaded to Git, although the size is much smaller than node_modules:

$ du -sh .yarn
190M    .yarn

$ du -sh .yarn/cache
61M     .yarn/cache

$ du -sh node_modules
507M    node_modules

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How to try

Switch to this branch and then run yarn first, yarn would extract cache for you, and then replace all npm run blahblah as yarn run blahblah

[cactbotbot]

@MaikoTan Thanks for your contribution! 🌵🚀

[MaikoTan]

The Github Actions CI failed because the --immutable flag for yarn install command was default to true in a CI environment

If the --immutable option is set (defaults to true on CI), Yarn will abort with an error exit code if the lockfile was to be modified (other paths can be added using the immutablePatterns configuration setting). For backward compatibility we offer an alias under the name of --frozen-lockfile, but it will be removed in a later release.

And somewhat that the checksum of packages from registry on Github Actions CI are not equal to those in the local lockfile, so cause the fail.

But even I run the command yarn install --immutable on my computer, it works fine. I don't know what's wrong with Github Actions, maybe change the registry to npmjs would solve the problem?

@JLGarber Can you try this PR and give me some feedback? I believe it is runnable now.

[MaikoTan]

As NPM now has part of Yarn Berry's features now, it would be better to just upgrade our npm version.