Update CI CPU badge

[glenn-jocher]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Updated Continuous Integration (CI) testing badge links in project documentation.

📊 Key Changes

• Modified badge links for CI CPU testing status in greetings.yml workflow file.
• Updated badge link for CI CPU testing in README.md.

🎯 Purpose & Impact

• Ensures that CI status badges reflect the correct and current status of CI testing workflows.
• Provides users with accurate, updated links to verify the operational status of YOLOv5 directly from the project's readme, enhancing transparency and trust.
• The updates may have a minor direct impact on the end user, but they improve the codebase's health and maintainability. 🛠️✅