fixed compilation error

seems there was excess parameter in new_debouncer() func, here is usage
example:

https://github.com/notify-rs/notify/blob/3df0f65152c8585cfb29d231c880b86b9164dcfd/examples/debouncer_mini.rs#L36

launchk/src/launchd/plist.rs

@@ -104,7 +104,7 @@ pub const SYSTEM_LAUNCH_DAEMONS: &str = "/System/Library/LaunchDaemons";
 
 async fn fsnotify_subscriber() {
     let (tx, rx): (Sender<DebounceEventResult>, Receiver<DebounceEventResult>) = channel();
-    let mut debouncer = new_debouncer(Duration::from_secs(5), None, tx).unwrap();
+    let mut debouncer = new_debouncer(Duration::from_secs(5), tx).unwrap();
     let watcher = debouncer.watcher();
 
     // Register plist paths