Fix discord badge in readme (#2975)

Update README.md

README.md

@@ -4,7 +4,7 @@
 
 [![Installation](https://img.shields.io/badge/docs-latest-green)](https://llm.mlc.ai/docs/)
 [![License](https://img.shields.io/badge/license-apache_2-blue)](https://github.com/mlc-ai/mlc-llm/blob/main/LICENSE)
-[![Join Discoard](https://img.shields.io/badge/Join-Discord-7289DA?logo=discord&logoColor=white)]("https://discord.gg/9Xpy2HGBuD")
+[![Join Discoard](https://img.shields.io/badge/Join-Discord-7289DA?logo=discord&logoColor=white)](https://discord.gg/9Xpy2HGBuD)
 [![Related Repository: WebLLM](https://img.shields.io/badge/Related_Repo-WebLLM-fafbfc?logo=github)](https://github.com/mlc-ai/web-llm/)
 
 **Universal LLM Deployment Engine with ML Compilation**