Added @nixon to maintainers list

Thanks a lot for your updates, mate!

Author: BurkovBA

README.md

@@ -93,5 +93,6 @@ Documentation available [here](https://github.com/umutbozkurt/django-rest-framew
 @qwiglydee
 @BurkovBA
 @Vayel
+@uixou
 
 Feel free to mail me if you consider being a maintainer.