Withdraw PEP 521 in favor of PEP 567 (gh-562)

pep-0521.txt

@@ -3,13 +3,18 @@ Title: Managing global context via 'with' blocks in generators and coroutines
 Version: $Revision$
 Last-Modified: $Date$
 Author: Nathaniel J. Smith <njs@pobox.com>
-Status: Deferred
+Status: Withdrawn
 Type: Standards Track
 Content-Type: text/x-rst
 Created: 27-Apr-2015
 Python-Version: 3.6
 Post-History: 29-Apr-2015
 
+PEP Withdrawal
+==============
+
+Withdrawn in favor of PEP 567.
+
 
 Abstract
 ========