Changes to Amend Order

added the new required request property qty

the price request property type changed from integer to string, and format from int64 to no format

the response property order_id became optional for the status 200

added OrderId subschema #1 to the order_id response property oneOf list for the response status 200

the order_id response's property type changed from string to no type, and format from uuid to no format for status 200

removed the request property size

endpoint added