Update README.md

Author: zachary62

README.md

@@ -82,7 +82,7 @@ This is a tutorial project of [Pocket Flow](https://github.com/The-Pocket/Pocket
    pip install -r requirements.txt
    ```
 
-4. Set up LLM in [`utils/call_llm.py`](./utils/call_llm.py) by providing credentials. By default, you can use the AI Studio key with this client for Gemini Pro 2.5:
+4. Set up LLM in [`utils/call_llm.py`](./utils/call_llm.py) by providing credentials. By default, you can use the [AI Studio key](https://aistudio.google.com/app/apikey) with this client for Gemini Pro 2.5:
 
    ```python
    client = genai.Client(