Update README.md

[glenn-jocher]

2-line update

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Enhanced documentation clarity on dataset exporting in README.

📊 Key Changes

• Updated the description related to the use of Roboflow with YOLOv5 in the README file.

🎯 Purpose & Impact

• 🎨 Improved clarity in language to better reflect the functionality of dataset labeling and exporting with Roboflow.
• ⚡ Users can understand the process more easily, potentially increasing the adoption of Roboflow for dataset preparation with YOLOv5.
• 👥 Non-expert users benefit from a more straightforward description, minimizing confusion about the Roboflow integration.