Update get_voc.sh data URLs

[WAMAWAMA]

The old VOC download address is not available. It is recommended to change to mirror

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Switched download source for VOC2007 dataset.

📊 Key Changes

• The source URL for downloading the VOC2007 trainval dataset has been updated.
• The source URL for downloading the VOC2007 test dataset has been changed.

🎯 Purpose & Impact

• These changes ensure the download links are working, as the previous URLs might be deprecated or less reliable.
• Users can now fetch the datasets without encountering download issues, allowing for smoother setup and experimentation with the YOLOv5 model. 🔄

[github-actions]

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

• Verify your PR is up-to-date with origin/master. If your PR is behind origin/master update by running the following, 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 rebase 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]

@WAMAWAMA thanks for the PR, I see you are correct about the site being down. I wonder if it's temporary or permanent...

Will merge PR in any case. Thank you for your contributions.