remove async when not necessary (#379)

Author: tjwald

lessons/231/python-app/main.py

@@ -39,12 +39,12 @@ def filter(self, record):
 
 
 @app.get("/healthz", response_class=PlainTextResponse)
-async def health():
+def health():
     return "OK"
 
 
 @app.get("/api/devices", response_class=ORJSONResponse)
-async def get_devices():
+def get_devices():
     devices = [
         {
             "id": 1,