Uploading untracked artifacts includes ignored files

Summary

Documentation says that files in .gitignore are not uploaded. However the code uses git ls-files -o which does not ignore ignored files. Hence, ignored files are also uploaded.

This is very undesirable as it creates huge artifacts in my setup.

Steps to reproduce

Just upload artifacts in a repo with .gitignore-d files.

Actual behavior

Uploads all untracked files.

Expected behavior

Should not upload ignored files.