Changes to Retrieve fees

the items/taxes/items response's property type changed from string to object for status 200

the query request parameter provider became optional

added the new enum value instant_payment to the query request parameter paymentMethod

added the non-success response with the status 400

added the required property items/taxes/items/feeId to the response with the 200 status

added the required property items/taxes/items/id to the response with the 200 status

added the required property items/taxes/items/taxType to the response with the 200 status

added the required property items/taxes/items/type to the response with the 200 status

added the required property items/taxes/items/value to the response with the 200 status