consider replace fxhash with rust-lang/rustc-hash

[Dushistov]

As user of bindgen, I am worry about two functionality duplicates in my dep tree:

https://github.com/rust-lang/rustc-hash
https://github.com/cbreeden/fxhash

May be you consider usage of rustc-hash instead of fxhash?

Advantages:

1. fxhash looks like "dead" repository
2. rustc-hash belong the same orgranization (rust-lang ) as bindgen

[emilio]

fxhash looks like "dead" repository

What makes you think that?

May be you consider usage of rustc-hash instead of fxhash?

Seems like the same hash, so sounds good, I'd be happy to merge a PR doing that switch :)