✨ feat(config): add result type to list_rules function

- modify list_rules to return a Result type
- allows for error handling during rule listing

src/config.rs

@@ -99,9 +99,10 @@ impl Config {
     }
 
     /// List the end of life rules set in the configuration
-    pub fn list_rules(&self) {
+    pub fn list_rules(&self) -> Result<(), Error> {
         for rule in &self.rules {
             println!("{rule}");
         }
+        Ok(())
     }
 }