Update hands-on-cleanrl.mdx

units/en/unit8/hands-on-cleanrl.mdx

@@ -111,10 +111,10 @@ virtual_display.start()
 For this exercise, we use `gym==0.21` because the video was recorded with Gym.
 
 ```python
-pip install gym==0.21
+pip install gym==0.22
 pip install imageio-ffmpeg
 pip install huggingface_hub
-pip install box2d
+pip install gym[box2d]==0.22
 ```
 
 ## Let's code PPO from scratch with Costa Huang's tutorial