Run a proper command ("make manifest" or "./Build manifest", maybe with a force option), or use a distribution builder to generate the MANIFEST. Or update MANIFEST manually.
Split the distribution, or fix the version numbers to make them consistent (use the highest version number to avoid version downgrade).
Add a META.json to the distribution. Your buildtool should be able to autogenerate it.
Add tests or move tests.pl to the t/ directory!
This is not a critical issue. Currently mainly informative for the CPANTS authors. It might be removed later.
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.