Add Ultralytics Discord badge

[glenn-jocher]

@Burhan-Q added Discord badge to Assets repo

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Added Discord badge to README for increased community engagement.

📊 Key Changes

• Inserted a Discord badge with a link to the Ultralytics Discord server into the README file.

🎯 Purpose & Impact

• Purpose: Encourage community interaction and provide a direct link for users to join the Ultralytics Discord community.
• Impact: Makes it easier for users to access support, engage with the Ultralytics team, and connect with fellow users, potentially leading to a more vibrant and active community. 🤝👥