remove dev1 from version

Author: mfranczel

setup.py

@@ -5,7 +5,7 @@
 
 setup(
     name='sqlalchemy-redshift',
-    version='0.8.15.dev1',
+    version='0.8.15',
     description='Amazon Redshift Dialect for sqlalchemy',
     long_description=readme + '\n\n' + history,
     long_description_content_type='text/x-rst',