Add finished to res (#117)

* add finished to res

This signals to Next that we aren't expecting any props to be returned in `getServersideProps` or `getInitialProps`

* Update createResponseObject.js

Author: JoviDeCroock

lib/templates/createResponseObject.js

@@ -75,6 +75,8 @@ const createResponseObject = ({ onResEnd }) => {
       }
     }
 
+    res.finished = true;
+    res.writableEnded = true;
     // Call onResEnd handler with the response object
     onResEnd(response);
   };