Deal with net-ftp being unavailable
Deal with net-ftp being unavailable

In Ruby 3.0 net-ftp changed from a bundled gem to a default gem. This
means it may not be available, such as when running unit tests.

Since ftp is becoming less and less common, this changes net-ftp to be
an optional dependency. Users who do need ftp support should ensure the
gem is installed.

puppetlabs/puppetlabs-apt