add a copyright notice

gevent/pywsgi.py

@@ -2,6 +2,7 @@
 #
 # Copyright (c) 2005-2006, Bob Ippolito
 # Copyright (c) 2007, Linden Research, Inc.
+# Copyright (c) 2009-2010, gevent contributors
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
 # in the Software without restriction, including without limitation the rights