Bump slackapi/slack-github-action from v3.0.2 to v3.0.3 in /.github/workflows

[UltralyticsAssistant]

Bump slackapi/slack-github-action from v3.0.2 to v3.0.3 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 Slack GitHub Action used in the publish workflow from v3.0.2 to v3.0.3 to keep notification automation current.

📊 Key Changes

• Upgraded the GitHub Action slackapi/slack-github-action in .github/workflows/publish.yml
• Updated both:
  • the success notification step ✅
  • the failure notification step ❌
• Version changed from v3.0.2 to v3.0.3

🎯 Purpose & Impact

• Helps keep the CI/CD workflow up to date 🔄
• May include small fixes, security updates, or compatibility improvements from the Slack Action maintainers 🛠️
• Reduces risk of issues in Slack notifications during package publishing 📦
• No change to core publish logic or user-facing package behavior, so impact is low and mainly focused on workflow reliability 👍