[6.x] Added OP.GG sponsor (#5121)

* Added OP.GG sponsor

* Update readme.md

readme.md

@@ -59,6 +59,7 @@ We would like to extend our thanks to the following sponsors for funding Laravel
 - [Abdel Elrafa](https://abdelelrafa.com)
 - [Hyper Host](https://hyper.host)
 - [Appoly](https://www.appoly.co.uk)
+- [OP.GG](https://op.gg)
 
 ## Contributing