cdc_csv_file's data as Zoltar's native list format, but only the "predictions" item, and not "meta"
Arguments
season_start_year
An integer specifying the "season" that cdc_csv_file is in. Used to convert EWs to
YYYY_MM_DD_DATE_FORMAT. zoltr uses week 30 as the season breakpoint, e.g. the "2016/2017 season" starts with