Renamed daily fearures

Cargo.toml

@@ -14,26 +14,26 @@ default = ["part1", "part2", "today"]
 part1 = []
 part2 = []
 today = []
-01 = []
-02 = []
-03 = []
-04 = []
-05 = []
-06 = []
-07 = []
-08 = []
-09 = []
-10 = []
-11 = []
-12 = []
-13 = []
-14 = []
-15 = []
-16 = []
-17 = []
-18 = []
-19 = []
-20 = []
+day01 = []
+day02 = []
+day03 = []
+day04 = []
+day05 = []
+day06 = []
+day07 = []
+day08 = []
+day09 = []
+day10 = []
+day11 = []
+day12 = []
+day13 = []
+day14 = []
+day15 = []
+day16 = []
+day17 = []
+day18 = []
+day19 = []
+day20 = []