docs(quick_start.md): add example of using proxy with litellm sdk

docs/my-website/docs/proxy/quick_start.md

@@ -283,6 +283,27 @@ response = client.chat.completions.create(model="gpt-3.5-turbo", messages = [
 
 print(response)
 
+```
+</TabItem>
+<TabItem value="litellm" label="LiteLLM SDK">
+
+```python
+from litellm import completion 
+
+response = completion(
+    model="openai/gpt-3.5-turbo", 
+    messages = [
+        {
+            "role": "user",
+            "content": "this is a test request, write a short poem"
+        }
+    ], 
+    api_key="anything", 
+    base_url="http://0.0.0.0:4000"
+    )
+
+print(response)
+
 ```
 </TabItem>
 <TabItem value="langchain" label="Langchain">