fix demo video

Author: apsinghdev

README.md

@@ -7,10 +7,7 @@ A real-time collaboration project to draw with your friends.
 
 ## Demo
 
-<video width="600" controls autoplay>
-  <source src="./demo.mp4" type="video/mp4"/>
-  Your browser does not support the video tag.
-</video>
+[![Demo video](https://markdown-videos-api.jorgenkh.no/url?url=https%3A%2F%2Fyoutu.be%2F74T8SncLnE8%3Fsi%3DUW4dB4Rs7_qqL6nn)](https://youtu.be/74T8SncLnE8?si=UW4dB4Rs7_qqL6nn)
 
 
 ## Instructions