Updated to new be-cordial-or-be-on-your-way URL and CoC now references Python Community CoC (#5811)

* Updated references to new be-cordial-or-be-on-your-way URL.

* CoC now references Python Community Code of Conduct

Author: MarkCBell

.github/CODE_OF_CONDUCT.md

@@ -1,3 +1,6 @@
-Be cordial or be on your way.
+# Treat each other well
 
-https://www.kennethreitz.org/essays/be-cordial-or-be-on-your-way
+Everyone participating in the _requests_ project, and in particular in the issue tracker,
+pull requests, and social media activity, is expected to treat other people with respect
+and more generally to follow the guidelines articulated in the
+[Python Community Code of Conduct](https://www.python.org/psf/codeofconduct/).

docs/dev/contributing.rst

@@ -34,7 +34,7 @@ including reporting bugs or requesting features. This golden rule is
 **All contributions are welcome**, as long as
 everyone involved is treated with respect.
 
-.. _be cordial or be on your way: https://www.kennethreitz.org/essays/be-cordial-or-be-on-your-way
+.. _be cordial or be on your way: https://kenreitz.org/essays/2013/01/27/be-cordial-or-be-on-your-way
 
 .. _early-feedback: