Gem::SpecificationPolicy#validate_required_ruby_version

# File tmp/rubies/ruby-4.0.0/lib/rubygems/specification_policy.rb, line 206
def validate_required_ruby_version
  if @specification.required_ruby_version.requirements == [Gem::Requirement::DefaultRequirement]
    warning "make sure you specify the oldest ruby version constraint (like \">= 3.0\") that you want your gem to support by setting the `required_ruby_version` gemspec attribute"
  end
end