Fix WindowSize not updating

bevy_kayak_renderer/src/lib.rs

@@ -27,6 +27,8 @@ pub struct WindowSize(pub f32, pub f32);
 fn update_window_size(
     mut window_resized_events: EventReader<WindowResized>,
     mut window_created_events: EventReader<WindowCreated>,
+    windows: Res<Windows>,
+    mut window_size: ResMut<WindowSize>,
 ) {
     let mut changed_window_ids = Vec::new();
     // handle resize events. latest events are handled first because we only want to resize each
@@ -48,6 +50,14 @@ fn update_window_size(
 
         changed_window_ids.push(event.id);
     }
+
+    for window_id in changed_window_ids {
+        if let Some(window) = windows.get(window_id) {
+            let width = window.width();
+            let height = window.height();
+            *window_size = WindowSize(width, height);
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy, Default)]