Support for setting PaymentIntent status directly upon creation

[basicallydan]

While using stripe-ruby-mock I tried to create a PaymentIntent with a status of requires_action to mimic being mid-flow of a 3D Secure process. It always ended up as 'succeeded' though.

Stripe::PaymentIntent.create(
  amount: amount,
  currency: 'usd',
  payment_method_types: ['card'],
  customer: user.customer,
  invoice: stripe_invoice.id,
  status: 'requires_action'
)

I had a look at the source code and realised that a specific amount is needed to set the status, 3184. There are other numbers for other statuses. What is the reason for status only being set indirectly via amount? I'd like to propose either allowing status to be set directly, or that the amount thing is documented somewhere other than spec to make it clearer. I'm happy to contribute some time to do or help do either one of these things.

Thanks for the hard work on this great library! I use it almost daily :)

[base10]

This feels like the sort of thing it'd be helpful to have a StripeMock.prepare_payment_intent(:insufficient_funds) or similar for.