Add ReceiptNumber and ReceiptEmail support
Add ReceiptNumber and ReceiptEmail support

As per [0], we support receipt_number and receipt_email in the
charge object in the Stripe API. Somehow, it looks like those did
not make their way into the java bindings.

This PR adds them.

[0] https://stripe.com/docs/api/java#charge_object

rgarbi/stripe-java,AdamStelmaszczyk/stripe-java,stripe/stripe-java,hardtoe/stripe-java,zs-engg/stripe-sdk,shalecraig/stripe-java,kbouzidi/stripe-java