Update to correct pip install for litellm (#2602)

The doc mentions `pip install litellm[proxy]` which won't work. The correct command is  `pip install 'litellm[proxy]'`.

website/docs/topics/non-openai-models/local-litellm-ollama.md

@@ -18,7 +18,7 @@ Note: We recommend using a virtual environment for your stack, see [this article
 Install LiteLLM with the proxy server functionality:
 
 ```bash
-pip install litellm[proxy]
+pip install 'litellm[proxy]'
 ```
 
 Note: If using Windows, run LiteLLM and Ollama within a [WSL2](https://learn.microsoft.com/en-us/windows/wsl/install).