You could import it through the UI:
However, if you want to be able to sync changes, I believe you’d need to pull to a local clone and then push from it. Something like this:
- Clone from GitLab
git clone "https://gitlab.com/manuelkostka/discourse/canvas/theme.git"
- Set push URL to your GitHub repo
git remote set-url --push origin "git@github.com:Username/Reponame.git"
- Then you can periodically fetch from GitLab and push to GitHub
git fetch -p origin
git push origin
