Update video link to actual YouTube video

Author: andrestubbe

README.md

@@ -6,7 +6,7 @@
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 [![JitPack](https://jitpack.io/v/andrestubbe/FastFileIndex.svg)](https://jitpack.io/#andrestubbe/FastFileIndex)
 
-[![Demo Screenshot](docs/demo-screenshot.png)](https://www.youtube.com/watch?v=YOUR_VIDEO_ID_HERE)
+[![Demo Screenshot](docs/demo-screenshot.png)](https://www.youtube.com/watch?v=69XEJ49yqbA)
 
 ## Table of Contents