wish: depend on request-promise-any instead of request-promise-native.

[markstos]

Thanks for this module.

I've got an app that uses request-promise that returns Bluebird promises that I'd like to add retries to.

This looks like a great module to use to help with that, but it appears to return native promises only.

If it depended on request-promise-any than users could choose which promises they want returned.

[disjunction]

done in 2.0.0