Use python.org instead of peps.io
diff --git a/docs/contributing.rst b/docs/contributing.rst
index 4bb1461..3afc89f 100644
--- a/docs/contributing.rst
+++ b/docs/contributing.rst
@@ -281,7 +281,7 @@
.. _`GitHub`: https://github.com/pyca/cryptography
.. _`our mailing list`: https://mail.python.org/mailman/listinfo/cryptography-dev
-.. _`PEP 8`: http://www.peps.io/8/
+.. _`PEP 8`: http://www.python.org/dev/peps/pep-0008/
.. _`syntax`: http://sphinx-doc.org/domains.html#info-field-lists
.. _`pytest`: https://pypi.python.org/pypi/pytest
.. _`tox`: https://pypi.python.org/pypi/tox