Let zest.releaser know where to get the version

setup.cfg

+[bdist_wheel]
+universal = 0
+
+[zest.releaser]
+python-file-with-version = src/gevent/__init__.py

src/gevent/__init__.py

@@ -15,7 +15,8 @@ _version_info = namedtuple('version_info',
 
 #: The programatic version identifier. The fields have (roughly) the
 #: same meaning as :data:`sys.version_info`
-version_info = _version_info(1, 2, 0, 'beta', 1)
+#: Deprecated in 1.2.
+version_info = _version_info(1, 2, 0, 'final', 1)
 
 #: The human-readable PEP 440 version identifier
 __version__ = '1.2b1.dev0'