Update CONTRIBUTING.md

Co-authored-by: Sophie Arana <[email protected]>

CONTRIBUTING.md

@@ -28,7 +28,7 @@ We welcome contributions of all kinds, be it code, documentation, or community e
 We follow the same instructions for submitting changes to the project as those developed by [The Turing Way](https://github.com/the-turing-way/the-turing-way/blob/main/CONTRIBUTING.md#making-a-change-with-a-pull-request). In short, there are five steps to adding changes to this repository:
 
 1. **Fork the Repository**: Start by [forking the AutoEmulate repository](https://github.com/alan-turing-institute/autoemulate/fork).
-2. **Make Changes**: Ensure your code adheres to the style guidelines and passes all tests.
+2. **Make Changes**: Ensure your code follows the existing code style ([PEP 8](https://peps.python.org/pep-0008/)) and passes all tests.
 3. **Commit and Push**: Use clear commit messages.
 4. **Open a Pull Request**: Ensure you describe the changes made and any additional details.