fix discord link (#126)

Author: wasaga

README.md

@@ -1,6 +1,6 @@
 Welcome to the Pomerium Chat, a minimal chat application for showcasing remote Model Context Protocol servers secured with [Pomerium](https://pomerium.com).
 
-[![Discord](https://img.shields.io/badge/Discord-blue?style=for-the-badge)](https://discord.gg/pWzshUdT)
+[![Discord](https://img.shields.io/badge/Discord-blue?style=for-the-badge)](https://discord.gg/rz8CaaSXk6)
 [![Docker](https://img.shields.io/badge/docker-%230db7ed.svg?style=for-the-badge&logo=docker&logoColor=white)](/docker-compose.yaml)
 
 https://github.com/user-attachments/assets/50a17106-a471-4f64-be81-982c09d4689e