post https://{environment}.masspay.io/{VERSION}/payout/attribute///
This POST endpoint is used to store user attributes, allowing you to associate additional data with a user token.
To use this endpoint, you need to provide the user_token, destination_token, and currency as parameters in the URL Path. You also need to provide the attribute values as JSON parameters in the Request body.
If existing attributes are already stored for the user, this call will override their values.