Changes to Get CFTC positioning

the query request parameter commodity was restricted to a list of enum values

the response property data/percentile_1y became nullable for the status 200

the response property data/week_change became nullable for the status 200

the data/week_change response's property type changed from object to integer for status 200

added the new enum value BRENT to the query request parameter commodity

added the new enum value GASOLINE to the query request parameter commodity

added the new enum value HEATING_OIL to the query request parameter commodity

added the new enum value NATURAL_GAS to the query request parameter commodity

added the new enum value WTI to the query request parameter commodity

added the optional property data/collected_at to the response with the 200 status

added the optional property data/coverage to the response with the 200 status

added the optional property data/published_at to the response with the 200 status

added the optional property data/report to the response with the 200 status

added the new optional query request parameter commodity

added the media type application/json for the response with the status 200

added the media type application/json for the response with the status 401

added the non-success response with the status 400

added the non-success response with the status 500