Update google_utils.py

[glenn-jocher]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Optimization of model downloading process in the YOLOv3 repository.

📊 Key Changes

• Removed the dependency on the GitHub API for downloading pre-trained models.
• Hard-coded model file names as fallback options directly into the script.

🎯 Purpose & Impact

• Simplifies the code: By avoiding the GitHub API call, the downloading process becomes more straightforward.
• Increases reliability: Directly including model names ensures that the download process is less likely to fail due to API issues.
• Ensures continuity: Users can download necessary model files without interruption, even if the GitHub API is down or rate-limited.