Braintree

* 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`

* Add `DisputeAccepted`, `DisputeDisputed`, and `DisputeExpired` webhook constants
* Add `three_d_secure_pass_thru` to `CreditCard.create`, `CreditCard.update`, `PaymentMethod.create`, `PaymentMethod.update`, `Customer.create`, and `Customer.update`.
* Add `Verification` validation errors for 3D Secure
* Add `payment_method_token` to `CreditCardVerificationSearch`
* Add `recurring_customer_consent` and `recurring_max_amount` to `authentication_insight_options` for `PaymentMethodNonce.create`
* Add `FileIsEmpty` error code
* Eliminates usage of mutable objects for function parameters. Resolves 113 Thank you maneeshd!