Add globby.stream

[futpib]

Fixes #83

This adds support for async iteration by adding globby.stream which returns a ReadableStream.

Node 10 introduced experimental async iterator support to ReadableStream so if supported by one's node version, one can use globby.stream in a for-await-of loop as witnessed by this test https://github.com/futpib/globby/blob/958e81505b1baa7d73e29dbe3468123032cce9cf/test.js#L85-L92

[sindresorhus]

You also need to update https://github.com/sindresorhus/globby/blob/master/index.d.ts

[sindresorhus]

Can you fix the merge conflicts?

[futpib]

I have addressed all the review comments 👌

[sindresorhus]

Thanks 🙌

You need to submit the PR URL here to claim the bounty: https://issuehunt.io/r/sindresorhus/globby/issues/83