feat(dlx): yarn create <starter-kit-package> as an alias to yarn dlx create-<starter-kit-package>

[paul-soporan]

What's the problem this PR addresses?

yarn create was removed in Yarn v2 as the yarn dlx command got added.

The problem is that many of the starter-kit projects still only list yarn create:

• React - create-react-app
• Next - create-next-app
• Nuxt - create-nuxt-app
• Electron Forge - create-electron-app

This can cause confusion to people who don't happen to read the CLI page on our website, as there's no other place where this change is mentioned.

You can also consider it as a small Yarn-exclusive QoL change. 😄

How did you fix it?

I added the yarn create command back as a hidden alias to yarn dlx.

yarn create [flags] <starter-kit-package> ... is now an alias to yarn dlx [flags] create-<starter-kit-package> ....

[arcanis]

Great! Can you add an integration test? You can just add a create-test-app fixture that generates a hello.txt file, and check whether calling yarn create test-app properly generates the file (and maybe add another test for the scope thing too).

[paul-soporan]

Done. I also fixed tests by changing packages/yarnpkg-core/sources to @yarnpkg/core.

[arcanis]

Perfect!