Update Emmett to v2.0.0a4 (#5482)

* Updated weppy framework to 1.0

* Updated weppy to 1.0.1

* Update Python/emmett to 2.0.0a4

frameworks/Python/emmett/requirements.txt

@@ -1,3 +1,3 @@
-emmett==2.0.0a3
+emmett==2.0.0a4
 psycopg2==2.8.4
 gunicorn==19.9.0