Cashier set Stripe Api Version in config

[Ronan-Lenor]

i saw that Stripe provide a way to set the Stripe API version
https://docs.stripe.com/building-plugins#set-api-version

Even thought that it is mentionned that you can change it in the Dashboard here:
https://github.com/laravel/cashier-stripe/blob/15.x/UPGRADE.md#stripe-api-version

it would be better to set it on Cashier level. So, that would insure that the project always use its corresponding Cashier/Stripe API version.