Update Stripe SDK to new recommended syntax

[driesvints]

stripe/stripe-php#771

https://github.com/stripe/stripe-php/wiki/Migration-to-StripeClient-and-services-in-7.33.0

[sonja-turo]

Was thinking of tackling this, but the Stripe documentation still uses the old way, so I'm wondering if this new model is an encouraged thing from Stripe? (although I do think it is better)

[driesvints]

I'd rather tackle this one myself at some point as it's a pretty delicate one. Also: not sure what you mean but I see the new syntax in their API docs.

[sonja-turo]

That's fine. Oddly, their API docs show the new syntax, but their standard docs show the old way (which was what I was initially referencing).