Replace request and then-sleep dependencies

[styfle]

This changes request to node-fetch.

And also then-sleep to a one-line function sleep.

Resolves out of date dependencies brought up by @bnb upon npm install.

[leo]

I don't think we should maintain our own code path for promise sleeping. That's what npm packages exist for.

[bnb]

@leo if the one liner was published as an npm module, would that be acceptable? Currently then-sleep adds 37 dependencies for something that can be published as a single line 😬

[leo]

if the one liner was published as an npm module, would that be acceptable?

@bnb Absolutely! That's what I thought we'd get. 🙏

[styfle]

@leo I replaced my sleep function for delay, which is a slightly larger version of what I wrote but it has zero dependencies.

https://packagephobia.now.sh/result?p=delay

[styfle]

Fixed in 6.1.0