Add a README to the distribution. It should contain a quick description of your module and how to install it.
Add a Changelog (best named 'Changes') to the distribution. It should list at least major changes implemented in newer versions.
Add all modules contained in this distribution to the META.yml field 'provides'. Module::Build or Dist::Zilla::Plugin::MetaProvides do this automatically for you.
This is not a critical issue. Currently mainly informative for the CPANTS authors. It might be removed later.