Add Cypress as testing browser project

[Tchoupinax]

By submitting this pull request, I promise I have read the contribution guidelines twice and ensured my submission follows it. I realize not doing so wastes the maintainers' time that they could have spent making the world better. 🖖

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[papb]

Cypress is indeed awesome :)

[sindresorhus]

While it does run on Node.js, it's not for Node.js users. I think it would be a better fit for https://github.com/sorrycc/awesome-javascript