Explicit git clone master

[glenn-jocher]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Optimization of initial setup process for YOLOv5 on AWS.

📊 Key Changes

• Modified the cloning command for the YOLOv5 repository in the AWS user data script.

🎯 Purpose & Impact

• Ensures that the latest master branch is specifically cloned during initial AWS environment setup.
• Prevents potential issues from default branch changes or from cloning other branches unintentionally.
• Provides users with a more reliable and predictable setup experience when deploying YOLOv5 on AWS instances. 🚀