fix(app): correct call signature

app.py

@@ -37,13 +37,16 @@ def respond(
     response = ""
 
     try:
-        for message in client.chat_completion(
-            messages,
+        chat_completion = client.chat.completions.create(
+            model="tgi",
+            messages=messages,
             max_tokens=max_tokens,
             stream=True,
             temperature=temperature,
             top_p=top_p,
-        ):
+        )
+
+        for message in chat_completion:
             token = message.choices[0].delta.content
 
             if token: