Fix Tuple2<Int, Int>

[BSteffaniak]

public static getYearAndDay(Long millis) -> Tuple2<Int, Int> {
    var Int year = DateTime.EPOCH_YEAR
    var Int day = millis / DateTime.SECS_DAY
    
    while (day >= (let size = getYearSize(year))) {
        day -= size
        year++
    }
    
    return new Tuple2(year, day)
}