Merge branch 'fix-main' into 'master'

unwrap() to unwrap_or()

See merge request mhart/DancingDroids!18

src/main.rs

@@ -125,7 +125,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         .get_matches();
 
     let mut robot_pool: Vec<Robot> = Vec::new();
-    let raw_conf = open_file(matches.value_of("file").unwrap())?;
+    let raw_conf = open_file(matches.value_of("file").unwrap_or("two_robots.txt"))?;
     Ok(())
 }