Update README.md

Author: dcblogdev

README.md

@@ -27,7 +27,7 @@ This package is a re-published, re-organised and maintained version of [pingpong
 With one big bonus that the original package didn't have: **tests**.
 
 ## upgrade
-To upgrade to version V11 follow [Upgrade Guide](https://laravelmodules.com/docs/v11/upgrade) on official document.
+To upgrade to version V12 follow [Upgrade Guide](https://laravelmodules.com/docs/v12/upgrade) on official document.
 
 ## Install