Try to fix embed youtube link

Author: jeromewu

apps/website/src/pages/playground.md

@@ -36,7 +36,7 @@ development!
 ffmpeg.wasm fundamentals.
 
 Demo Video:
-<iframe style={{"aspect-ratio": "16 / 9", width: "100%"}} src="https://www.youtube.com/embed/F01B0fV20QA" title="YouTube video player" frameborder="0" allowfullscreen></iframe>
+<iframe style={{"aspect-ratio": "16 / 9", width: "100%"}} src="https://youtube.com/embed/F01B0fV20QA" title="YouTube video player" frameborder="0" allowfullscreen></iframe>
 
 [YouTube Video Link](https://www.youtube.com/watch?v=F01B0fV20QA)