chore: add a link to the license badge on README.md (#1647)

Author: Olexandr88

README.md

@@ -24,7 +24,7 @@
 
 ## Status
 
-![GitHub License](https://img.shields.io/github/license/supabase/realtime)
+[![GitHub License](https://img.shields.io/github/license/supabase/realtime)](https://github.com/supabase/realtime/blob/main/LICENSE)
 [![Coverage Status](https://coveralls.io/repos/github/supabase/realtime/badge.svg?branch=main)](https://coveralls.io/github/supabase/realtime?branch=main)
 
 | Features         | v1  | v2  | Status |