Update is_writeable() for 2 methods

[glenn-jocher]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Enhanced directory write permission checking in Ultralytics YOLOv5's utility functions.

📊 Key Changes

• 🛠️ Modified the is_writeable function in utils/general.py to include two methods for checking directory write permissions.
• ✨ Added a test parameter to the existing function to toggle between the original file creation method (method 1) and a new method using os.access (method 2).

🎯 Purpose & Impact

• 💡 The purpose is to improve the reliability of the write permission check across different environments, including potential edge cases on Windows.
• 🔒 Potential Impact: Provides users and developers with a more robust way to determine if a directory is writeable, which can prevent errors and improve the overall experience when interacting with file systems.