Upgrade the bundled version of Module::Install to at least 0.89, but preferably to the most current release. Alternatively, you can switch to another build system / installer that does not suffer from this problem. (ExtUtils::MakeMaker, Module::Build both of which have their own set of problems.)
Add a META.json to the distribution. Your buildtool should be able to autogenerate it.
This is not a critical issue. Currently mainly informative for the CPANTS authors. It might be removed later.
Add a 'repository' resource to the META.yml via 'meta_add' accessor (for Module::Build) or META_ADD parameter (for ExtUtils::MakeMaker).