Update license badge in README.md

Author: ZimengXiong

README.md

@@ -2,7 +2,7 @@
 
 # ExcaliDash v0.1.0
 
-[![License](https://img.shields.io/badge/license-MIT-blue.svg)](LICENSE)
+![License](https://img.shields.io/github/license/zimengxiong/excalidash)
 [![Docker](https://img.shields.io/badge/docker-ready-blue.svg)](https://hub.docker.com)
 
 A self-hosted dashboard and organizer for [Excalidraw](https://github.com/excalidraw/excalidraw) with live collaboration features.