Take a look at the META.yml Spec at https://metacpan.org/pod/CPAN::Meta::History::Meta_1_4 (for version 1.4) or https://metacpan.org/pod/CPAN::Meta::Spec (for version 2), and change your META.yml accordingly.
Error: License 'gpl2' is invalid (license) [Validation: 1.4]
Change the permissions of Build.PL/Makefile.PL to not-executable.
Add a META.json to the distribution. Your buildtool should be able to autogenerate it.
Move your *.pm files in a directory named 'lib'. The directory structure should look like 'lib/Your/Module.pm' for a module named 'Your::Module'. If you need to provide additional files, e.g. for testing, that should not be considered for Kwalitee, then you should look at the 'provides' map in META.yml to limit the files scanned; or use the 'no_index' map to exclude parts of the distribution.
Add 'use warnings' (or its equivalents) to all modules, or convince us that your favorite module is well-known enough and people can easily see the modules warn when something bad happens.
Split the distribution, or fix the version numbers to make them consistent (use the highest version number to avoid version downgrade).
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.