Merge a fork by @lucasbstn

[O-Hannonen]

Hi!

I am working on an application that needs to create payment methods, attach payment methods to customers and create subscriptions. Since this package does not utilize those endpoints from Stripe API, I was planning on creating a PR where those would be included. Before forking, I looked at the forks already created, and stumbled upon this fork by @lucasbstn.

That fork has implemented all the endpoints I need, and I think they would benefit a lot of other people as well. Therefore I am requesting that those changes could be merged to this package itself.