GithubBackup uses "github-cli" to grab all repos (public & private) as using the base api only can grab public. You can setup gh auth to either use your login or an ssh key and enable ssh or https clones in regards to your preference.
GITHUB CLI: https://cli.github.com/
./backup.sh <BACKUP-LOCATION>
./backup.sh ~/Documents
./backup.sh "/mnt/id7/GITHUB_BACKUPS"
./backup.sh "/run/media/U5B/GITHUB_BACKUPS"