Changes to Create an inventory return location

added the new required request property data/relationships/inventory_model/data

added the new required request property data/relationships/stock_location/data

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

removed the request property data/relationships/inventory_model/id

removed the request property data/relationships/inventory_model/type

removed the request property data/relationships/stock_location/id

removed the request property data/relationships/stock_location/type

the type request property default value inventory_return_locations was removed

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

added the media type application/vnd.api+json for the response with the status 201