The easiest way to get going with this version is to first install the original apt-mirror from the Ubuntu repo.
sudo apt install apt-mirror
Make a backup of the original file that was installed.
sudo cp /usr/bin/apt-mirror /usr/bin/apt-mirror.original
Next clone this repo somewhere on your local system, and then copy or symlink this version to the location /usr/bin/apt-mirror overwriting it.
Either way if you copy or symlink, change the permissions.
sudo chown root:root /usr/bin/apt-mirror && sudo chmod 755 /usr/bin/apt-mirror
Please be patient, I don't get a lot of foot traffic here, and might be a week before I see an issue or a PR. You are welcome to dm/ping me if you feel its urgent enough.