Update format.yml for Issue autolabel

[glenn-jocher]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Improved GitHub workflow configuration for better formatting and issue management.

📊 Key Changes

• Trigger workflow on new or edited issues.
• Limited pull request workflows to the main branch.
• Enhanced token handling with a fallback option.
• Enabled auto-labeling for issues and PRs.
• Added prettier for YAML formatting.

🎯 Purpose & Impact

• Enhanced Issue Handling: Automatically formats and labels new or edited issues to ensure consistency and ease of tracking. 🏷️
• Improved Code Quality: Additional formatting options help maintain codebase readability and organization. 🧹
• Efficiency: Better token management ensures secure and smooth workflow operations. 🔐
• Focused PR Management: Limiting to the main branch simplifies workflows and reduces unnecessary processing. 🚀