Changes to Create a new task

added the optional property reviewed_at to the response with the 201 status

the response property file_upload became nullable for the status 201

the response property storage_filename became nullable for the status 201

the agreement response's property type changed from string to number, and format from no format to double for status 201

the agreement_selected response's property type changed from string to number, and format from no format to double for status 201

the annotations response's property type changed from string to array for status 201

the response property annotation_time became nullable for the status 201

the response property review_time became nullable for the status 201

the annotators/items response's property type changed from integer to object for status 201