Add demo

Author: EmilienM

README.md

@@ -5,7 +5,7 @@ Click [here](https://shiftstack.github.io/hcp-cli-assistant/) to open the assist
 An interactive web UI wizard that helps users generate the correct `hcp create cluster` commands.
 The assistant guides users step-by-step through required and optional configurations, ensuring a smooth setup experience.
 
-![UI screenshot](screenshot.png?raw=true "UI screenshot")
+![UI demo](demo.gif?raw=true "UI demo")
 
 ## Features
 - Step-by-step wizard for easy input