fix: remove erroneous -- from git checkout command

[saschabuehrle]

Bug

#40 — Public repository deployments fail with pathspec did not match any file(s) known to git because the git checkout command places the commit SHA after --, which tells git to treat it as a pathspec (file path) instead of a commit reference.

Fix

Remove the -- argument from the git checkout invocation in download_repo.rs. Per the git manual, arguments after -- are interpreted as pathspecs, not as tree-ish references. The commit SHA should be passed directly to git checkout without the -- separator.

Before: git checkout -- <commit_sha>
After: git checkout <commit_sha>

Testing

Verified locally that git checkout <sha> correctly checks out the target commit, whereas git checkout -- <sha> fails with the reported pathspec error when the SHA does not match a filename.

Happy to address any feedback.

Greetings, saschabuehrle