Update README.md

client.py is no longer there in the worker templates.

workers/hello_world/README.md

@@ -30,7 +30,6 @@ All PyWorkers have four files:
         ├── __init__.py
         ├── data_types.py # contains data types representing model API endpoints
         ├── server.py # contains endpoint handlers
-        ├── client.py # a script to call an endpoint through the autoscaler
         └── test_load.py # script for load testing
 
 ```