Comment 3 for bug 1862700

I was able to download the box linked to by Eric and add manually and that worked. For anyone else looking to do the same, after downloading you'll want to do the following from where the file was downloaded:

vagrant box add bionic-server-cloudimg-amd64-vagrant.box --name=ubuntu/bionic64

You could specify another name if desired...though I'm hoping that maybe it will see future upgrades since I named it identically to what it would be named if downloaded through the normal mechanisms...