Change openstack-dev to openstack-discuss

Mailinglists have been updated. Openstack-discuss replaces openstack-dev.

Change-Id: I207676942af280d1cabb406fa3c6757b7da61123

setup.cfg

@@ -16,7 +16,7 @@ classifiers =
     License :: OSI Approved :: Apache Software License
     Operating System :: POSIX :: Linux
 author = OpenStack
-author-email = openstack-dev@lists.openstack.org
+author-email = openstack-discuss@lists.openstack.org
 home-page = https://docs.openstack.org/python-mistralclient/latest/
 
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