RUN git clone instead of COPY to /usr/src/app

[glenn-jocher]

Avoid the need for a separate /yolov5 git clone directory.

Problem with COPY . /usr/src/app is that directory is not a .git directory, so normal ops like git pull etc don't work in Docker currently. This should resolve this issue.

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Improvement of Dockerfile configurations for YOLOv5 repository cloning.

📊 Key Changes

• Removed the COPY . /usr/src/app command in Dockerfiles across multiple architectures (default, ARM64, CPU).
• Replaced with RUN git clone https://github.com/ultralytics/yolov5 /usr/src/app to directly clone the YOLOv5 repo into the working directory.

🎯 Purpose & Impact

• 🛠 Fixes issues related to the Docker container not recognizing a .git directory due to the previous COPY command.
• ✅ Ensures a smoother setup and deployment process for users employing Docker, leading to a more reliable development and testing environment.
• 🚀 Potential to increase user satisfaction with the YOLOv5 Docker implementation as it alleviates past configuration issues.

[glenn-jocher]

@AyushExel this should let us work directly from the default Docker WORKDIR, i.e. usr/src/app. It will now be a full git clone directory, with /yolov5 removed.

i.e. directly on entering a docker container you should be able to git pull, git checkout classifier etc. which isn't possible now and the reason I had a separate /yolov5 dir next to the /app dir.