Changes to Update a return line item

request property data/type was restricted to a list of enum values

the request property data/attributes/metadata became nullable

the request property data/attributes/reference became nullable

the request property data/attributes/reference_origin became nullable

the request property data/attributes/return_reason became nullable

the type request property default value return_line_items was removed

added the new return_line_items enum value to the request property data/type

added the media type application/vnd.api+json for the response with the status 200