update the update the day modules of easier usage of the alt flag

src/cli/commands/day021.rs

@@ -3,6 +3,10 @@ use std::fs::File;
 use std::io::{BufReader,Lines};
 use crate::util::read_lines;
 
+fn part1(lines: Lines<BufReader<File>>) {
+
+}
+
 pub fn subcmd_day021(file: &Option<PathBuf>, alt: &bool) {
     if let Ok(lines) = read_lines(file.as_ref().unwrap().as_path()) {