Braintree

* Add `merchant_account_id` to `Transaction.refund`
* Add `Transaction.adjust_authorization` method to support for multiple authorizations for a single transaction

* Add `installments` to `Transaction` requests
* Add `count` to `installments`
* Deprecate `device_session_id` and `fraud_merchant_id` in `CreditCardGateway`, `CustomerGateway`, `PaymentMethodGateway`, and `TransactionGateway` classes
* Add `sca_exemption` to Transaction.sale request

* Add `acquirer_reference_number` to `Transaction`
* Deprecate `recurring` in Transaction sale requests

* Deprecate `masterpass_card` and `amex_checkout_card` payment methods
* Fix issue where `transaction.credit` could not be called using a gateway object

* Add validation error code `Transaction.ProductSkuIsInvalid`
* Add 'RiskThreshold' gateway rejection reason
* Add `processed_with_network_token` to `Transaction`
* Add `is_network_tokenized` to `CreditCard`

* Add `retrieval_reference_number` to `Transaction`
* Add `network_transaction_id` to `CreditCardVerification`
* Add `product_sku` to `Transaction`
* Add `customer_device_id`, `customer_location_zip`, and `customer_tenure` to `RiskData`
* Add `phone_number` and `shipping_method` to `Address`
* Add validation error codes:
* `Transaction.ShippingMethodIsInvalid`
* `Transaction.ShippingPhoneNumberIsInvalid`
* `Transaction.BillingPhoneNumberIsInvalid`
* `RiskData.CustomerBrowserIsTooLong`
* `RiskData.CustomerDeviceIdIsTooLong`
* `RiskData.CustomerLocationZipInvalidCharacters`
* `RiskData.CustomerLocationZipIsInvalid`
* `RiskData.CustomerLocationZipIsTooLong`
* `RiskData.CustomerTenureIsTooLong`