Added YOLOv5_AUTOINSTALL environment variable

[jkocherhans]

Setting the environment variable YOLOv5_AUTOINSTALL=False will skip installing any missing dependencies as if the user had passed install=False to check_requirements.

See discussion #7472 for details.

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Enhanced control over automatic dependencies installation in YOLOv5.

📊 Key Changes

• A new AUTOINSTALL global variable was introduced.
• Conditional check for auto-installation of requirements based on the AUTOINSTALL environment variable.

🎯 Purpose & Impact

• 🎛️ Purpose: The change allows users to control whether dependencies should be automatically installed by setting an environment variable YOLOv5_AUTOINSTALL.
• 🔧 Impact: Developers who prefer manual control over their environment can disable auto-install. Users can expect more predictable behavior in environments where automatic changes are restricted or not desired.

[github-actions]

👋 Hello @jkocherhans, thank you for submitting a YOLOv5 🚀 PR! To allow your work to be integrated as seamlessly as possible, we advise you to:

• ✅ Verify your PR is up-to-date with upstream/master. If your PR is behind upstream/master an automatic GitHub Actions merge may be attempted by writing /rebase in a new comment, or by running the following code, replacing 'feature' with the name of your local branch:

git remote add upstream https://github.com/ultralytics/yolov5.git
git fetch upstream
# git checkout feature  # <--- replace 'feature' with local branch name
git merge upstream/master
git push -u origin -f

• ✅ Verify all 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

[glenn-jocher]

@jkocherhans PR is merged. Thank you for your contributions to YOLOv5 🚀 and Vision AI ⭐