rewrite contributing

Author: KommuSoft

CONTRIBUTING.md

@@ -1,5 +1,5 @@
 # Contributing to REST framework
 
-At this point in its lifespan we consider Django REST framework to be essentially feature-complete. We may accept pull requests that track the continued development of Django versions, but would prefer not to accept new features or code formatting changes.
+At this point in its lifespan we consider Django REST framework to be essentially feature-complete. We may accept pull requests that track the continued development of Django versions, but would prefer not to accept new features or code formatting or performance increasing changes.
 
 The [Contributing guide in the documentation](https://www.django-rest-framework.org/community/contributing/) gives some more information on our process and code of conduct.