Update Actions with Lychee and GitHub Token

[pderrenger]

This pull request adds an improved Ultralytics Actions workflow to automatically format code and documentation to the new Ultralytics official standards maintained at https://github.com/ultralytics/actions.

Five individual actions are run by default now including a new broken links check for markdown and HTML files. Disable individual actions by setting them to false or removing their line, i.e. delete 'markdown: true' line to disable markdown formatting.

To customize an action use a pyproject.toml file in this repo. For details see https://github.com/ultralytics/actions.

# Ultralytics 🚀 - AGPL-3.0 license
# Ultralytics Actions https://github.com/ultralytics/actions
# This workflow automatically formats code and documentation in PRs to official Ultralytics standards

name: Ultralytics Actions

on:
  push:
    branches: [main]
  pull_request_target:
    branches: [main]

jobs:
  format:
    runs-on: ubuntu-latest
    steps:
      - name: Run Ultralytics Formatting
        uses: ultralytics/actions@main
        with:
          token: ${{ secrets.GITHUB_TOKEN }}  # automatically generated
          python: true
          docstrings: true
          markdown: true
          spelling: true
          links: true

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Improvement to the GitHub Actions formatting workflow in the Ultralytics YOLOv3 repository.

📊 Key Changes

• Trigger changed from pull_request to pull_request_target.
• New secret token usage in the formatting action.
• Added link verification to the formatting checks.

🎯 Purpose & Impact

• The trigger adjustment allows workflow runs to have write permissions, enabling more actions on pull request events.
• The secret token enables actions that require authentication, such as posting comments, or labeling PRs, enhancing automation capabilities.
• The link verification helps maintain the integrity of the documentation, ensuring all hyperlinks are valid and accessible.

Overall, these changes will make the repository's continuous integration processes more robust and helpful for maintaining high-quality code and documentation. 🚀

[github-actions]

👋 Hello @pderrenger, thank you for submitting a YOLOv3 🚀 PR! To allow your work to be integrated as seamlessly as possible, we advise you to:

• ✅ Verify your PR is up-to-date with ultralytics/yolov3 master branch. If your PR is behind you can update your code by clicking the 'Update branch' button or by running git pull and git merge master locally.
• ✅ Verify all YOLOv3 Continuous Integration (CI) checks are passing.
• ✅ Reduce changes to the absolute minimum required for your bug fix or feature addition. "It is not daily increase but daily decrease, hack away the unessential. The closer to the source, the less wastage there is." — Bruce Lee