fix bug in generated gemspec for Ruby 3.3

Author: davetron5000

lib/gli/commands/scaffold.rb

@@ -121,7 +121,7 @@ def self.mk_rakefile(root_dir,dry_run,project_name,create_test_dir)
   rd.title = 'Your application title'
 end
 
-spec = eval(File.read('#{project_name}.gemspec'))
+spec = Gem::Specification.load("#{project_name}.gemspec")
 
 Gem::PackageTask.new(spec) do |pkg|
 end