Sorry for the late reply. I figured out what the problem is:
this is the link to the instructions
system is Ubuntu 20.04.1 LTS, fresh
install on a virtual machine
everything seems to be working thus
far, but I've still got a bit of setting up to go.
We don't list any modules from Perl Core (those that come with Perl by default on all platforms because they ship with Perl) in our dependency listing. However, Perl 5.30 - the one in Ubuntu 20.04 - removed Locale::Codes, which includes Locale::Country.
Meaning that you need to run the correction you did: sudo cpanm Locale::Country
I'll make sure the Locale::Country dependency is included for perls 5.30 and later!