Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -9,11 +9,8 @@ Please, don't use the issue tracker for support questions.
 # Ground Rules
 Responsibilities
 * Ensure cross-platform compatibility for every change that's accepted. Windows, Mac, Debian & Ubuntu Linux.
-* Ensure that code that goes into core meets all requirements in this checklist: https://gist.github.com/audreyr/4feef90445b9680475f2
 * Create issues for any major changes and enhancements that you wish to make. Discuss things transparently and get community feedback.
-* Don't add any classes to the codebase unless absolutely needed. Err on the side of using functions.
 * Keep feature versions as small as possible, preferably one new feature per version.
-* Be welcoming to newcomers and encourage diverse new contributors from all backgrounds. See the [Python Community Code of Conduct](https://www.python.org/psf/codeofconduct/).
 
 # Getting started
 1. Create your own fork of the code