Yarn v2 support

[pustovalov]

Hey,

I have this declaration for size-limit in package.json

"devDependencies": {
  "@size-limit/preset-app": "^3.0.0",
  "@size-limit/webpack": "^3.0.0"
}

with yarn v1 everything worked well, but with yarn 2 and PnP, I got this an error message:

[~/site-new]$ yarn size                                                                                                                                               
Usage Error: Couldn't find a script named "size-limit".

$ yarn run <scriptName> ...

[~/site-new]$ yarn bin                                                                                                                                               
➤ YN0000: husky-run
➤ YN0000: husky-upgrade
➤ YN0000: lint-staged
➤ YN0000: prettier
➤ YN0000: sass
➤ YN0000: webpack
➤ YN0000: webpack-bundle-analyzer
➤ YN0000: webpack-cli
➤ YN0000: webpack-dev-server
➤ YN0000: Done in 0.04s

After I changed the declaration to:

"devDependencies": {
  "@size-limit/preset-app": "^3.0.0",
  "@size-limit/webpack": "^3.0.0",
  "size-limit": "^3.0.0"
}

[~/site-new]$ yarn size                                                                                                                                               
 WARN  You can remove size-limit dependency
       All plugins and presets already contain it as own dependency
       yarn remove size-limit

[~/site-new]$ yarn bin                                                                                                                                                
➤ YN0000: husky-run
➤ YN0000: husky-upgrade
➤ YN0000: lint-staged
➤ YN0000: prettier
➤ YN0000: sass
➤ YN0000: size-limit
➤ YN0000: webpack
➤ YN0000: webpack-bundle-analyzer
➤ YN0000: webpack-cli
➤ YN0000: webpack-dev-server
➤ YN0000: Done in 0.05s

[pustovalov]

as I understand yarn 2 applies binaries only from first level dependencies, discussion with the maintainer of yarnpkg:

[ai]

We can change Install instruction to explicitly ask to add size-limit to dependencies and remove the warning.

[pustovalov]

I can make a PR for these changes, today or tomorrow