Updated version to 2.0.0

Author: syrusakbary

setup.py

@@ -4,7 +4,7 @@
 
 setup(
     name="Flask-GraphQL",
-    version="2.0",
+    version="2.0.0",
     description="Adds GraphQL support to your Flask application",
     long_description=open("README.rst").read(),
     url="https://github.com/graphql-python/flask-graphql",