fix compiler error

src/main.rs

@@ -379,6 +379,7 @@ async fn main() {
         let running = Arc::new(Mutex::new(0));
         println!("encode: encoding gifs...");
         for n in 0..((dir as f32 / (25.0 * 5.0)).ceil() as usize) {
+            {
                 let running = running.clone();
                 thread::spawn(move || {
                     *running.lock().unwrap() += 1;
@@ -433,6 +434,7 @@ async fn main() {
                     *running.lock().unwrap() -= 1;
                     println!("encode: encoded {n}");
                 });
+            }
             while *running.lock().unwrap() < 5 {
                 tokio::time::sleep(Duration::from_millis(100)).await;
             }