[WIP] Bring typings from DefinitelyTyped into this repo

[samtsai]

What:
Improve support of typings by bringing them into this repo instead of relying on a versioned external repo

Why:
Help with stability for consumers using typings and give a clearer understanding of what should be supported in a given version without having to reference multiple repos.

How:
Modeled after these changes in a sibling repo: testing-library/dom-testing-library#530

Checklist:

• Documentation added to the
  docs site
• Tests
• Typescript definitions updated
• Ready to be merged
  

Currently this does not validate with several errors for Typescript@4.0, example:

ERROR: 6:23   expect      TypeScript@4.0 compile error:
Cannot use JSX unless the '--jsx' flag is provided.

I'm still investigating this, but if anyone knows more about dtslint I'm all 👂

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[samtsai]

Bumped this from 3.1 to 3.8 for this support:
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-8.html#type-only-imports-and-exports

[kentcdodds]

Looks awesome. I don't know about the dtslint stuff, but once that's worked out I'm good to merge 👍 Thanks!

[codecov]

Codecov Report

Merging #690 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #690   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            4         4           
  Lines           99        99           
  Branches        15        15           
=========================================
  Hits            99        99           

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[kentcdodds]

Sweet! Thanks!

[kentcdodds]

@all-contributors please add @samtsai for code and tests

[allcontributors]

@kentcdodds

I've put up a pull request to add @samtsai! 🎉

[kentcdodds]

🎉 This PR is included in version 10.1.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[kentcdodds]

Thanks so much for your help! I've added you as a collaborator on the project. Please make sure that you review the other/MAINTAINING.md and CONTRIBUTING.md files (specifically the bit about the commit messages and the git hooks) and familiarize yourself with the code of conduct (we're using the contributor covenant). You might also want to watch the repo to be notified when someone files an issue/PR. Please continue to make PRs as you feel the need (you can make your branches directly on the repo rather than your fork if you want). Thanks! And welcome to the team :)