Update readme

Author: jenssegers

README.md

@@ -38,7 +38,7 @@ composer require jenssegers/mongodb
  4.2.x    | 2.0.x
  5.0.x    | 2.1.x
  5.1.x    | 2.2.x or 3.0.x
- 5.2.x    | 2.2.x or 3.0.x
+ 5.2.x    | 2.3.x or 3.0.x
 
 And add the service provider in `config/app.php`: