Bump actions/checkout from v6 to v7 in /.github/workflows

[UltralyticsAssistant]

Bump actions/checkout from v6 to v7 in /.github/workflows

This PR updates GitHub Actions references in this repository.

Examples:

• Branch: actions/checkout@main stays on @main
• Major tag: actions/checkout@v4 updates to @v5
• Specific tag: astral-sh/setup-uv@v0.5.0 updates to @v0.9.4
• SHA pinned: actions/checkout@<sha> # v4.1.0 updates to the latest release SHA and tag comment

_{Made with ❤️ by Ultralytics Actions}

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

🔄 This PR updates the GitHub Actions checkout step in CI from actions/checkout@v6 to actions/checkout@v7 to keep the automation workflow current.

📊 Key Changes

• ⬆️ Updated .github/workflows/ci.yml
• 🔧 Changed the CI workflow dependency from actions/checkout@v6 to actions/checkout@v7
• ✅ No model, training, or inference code was modified

🎯 Purpose & Impact

• 🛡️ Keeps the repository’s CI pipeline aligned with the latest GitHub Actions version
• 🚀 May improve workflow reliability, compatibility, and access to upstream fixes
• 👥 Low-risk maintenance update with little to no direct impact on end users, but helps developers by keeping automated testing healthy and up to date