added script for new day

src/main.rs

@@ -15,6 +15,7 @@ fn main() {
         (8, day08::day_main),
         (9, day09::day_main),
         (10, day10::day_main),
+        // PLACEHOLDER
     ]);
     let day: Option<u8> = args().nth(1).and_then(|a| a.parse().ok());
     let Some(day) = day else {