Update stale.yml

[glenn-jocher]

Update to keep PR's open longer before stale.

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Adjusting GitHub Stale Bot configuration for issues and PRs 🤖✨

📊 Key Changes

• Split the stale and close days settings for issues and pull requests.
• Issues will now become stale after 30 days and closed after 10 days.
• Pull requests will become stale after 90 days and closed after 30 days.

🎯 Purpose & Impact

• 🛠️ Customized management: Differentiating between the management of issues and PRs allows for more tailored workflows.
• ⏰ Extended evaluation time for PRs: Developers have more time to review and work on PRs before they're marked as stale or closed.
• 🔄 Increased operational limit: More operations per bot run helps in managing a larger backlog of stale items.
• 🔓 User benefit: Contributors have clearer expectations and more time to respond to activity on their PRs, reducing the chance of valuable contributions getting closed prematurely.