Use WHATWG URL to format the URL for the cache key

[sindresorhus]

Here: https://github.com/lukechilds/cacheable-request/blob/847786f24115cb66bacebc3f9b75c14cc56ae149/src/index.js#L43

[jstewmon]

@lukechilds I've tried to thoroughly explain the problem in sindresorhus/got#519 (comment).

I think cacheable-request intends to support the same interface as http.request based on the docs:

Request function to wrap with cache support. Should be http.request or a similar API compatible request function.

So, I'd like to fix this by formatting the cache key according to one of the supported argument types for http.request: string, URL or object.

We can still check for the cache-specific options as properties on a URL instance, but I'm not sure anyone would ever want to provide them that way. I'll work up a PR.

[jstewmon]

I think this is closed by #43?

[sindresorhus]

Yup