Change openstack-dev to openstack-discuss

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

Change-Id: Id639a45680b149ca1ffe8e91fcdea713576b355d

Author: QingsZhao

setup.cfg

@@ -4,7 +4,7 @@ summary = OpenStack DevStack
 description-file =
     README.rst
 author = OpenStack
-author-email = openstack-dev@lists.openstack.org
+author-email = openstack-discuss@lists.openstack.org
 home-page = https://docs.openstack.org/devstack/latest
 classifier =
     Intended Audience :: Developers