Bump slackapi/slack-github-action from v3.0.5 to v4.0.0 in /.github/workflows

[UltralyticsAssistant]

Bump slackapi/slack-github-action from v3.0.5 to v4.0.0 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

Upgraded the GitHub Actions Slack notification integration from v3.0.5 to v4.0.0. 🔄

📊 Key Changes

• Updated the Slack GitHub Action used for release success notifications to slackapi/slack-github-action@v4.0.0.
• Updated the Slack GitHub Action used for release failure notifications to slackapi/slack-github-action@v4.0.0.
• Preserved the existing webhook configuration, notification content, and success/failure conditions.

🎯 Purpose & Impact

• Keeps release notifications aligned with the latest supported Slack Action version. ✅
• May provide improved compatibility, maintenance, and security through the newer action release.
• Does not change the notification behavior or affect the publishing process itself.