post https://sandbox.pismolabs.io/upi-gateway/v1/cards/transfer
United Payments Interface (UPI) funds transfer for RuPay, an Indian card network.
This endpoint generates a Payment methods authorization created event and a Platform authorization created event.
This operation is idempotent, meaning, it can be applied multiple times, yet the outcome remains the same. To guarantee this, the request has an external_transaction_id field, which must be unique by transaction type in the context of the same account reference number.