update ci-testing.yml with on: cron

[glenn-jocher]

Signed-off-by: Glenn Jocher glenn.jocher@ultralytics.com

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Enhanced CI testing and streamlined workflow greetings.

📊 Key Changes

• CI testing now includes scheduled runs with a CRON job.
• Greetings workflow messages have been reformatted for clarity.
• Stale action schedules have been corrected for consistency.

🎯 Purpose & Impact

• 🕒 Scheduled CI Runs: Ensures regular testing even without code changes, leading to early detection of issues from external dependencies.
• 👋 Improved PR Greetings: Aims to provide clearer contribution guidance and improve the quality of incoming PRs.
• 🚀 Stale Actions Fix: Improves automation for managing stale issues and PRs, keeping the project's issue backlog relevant and manageable.

[glenn-jocher]

Includes PyCharm linting on all action yamls.