Rakefile in rubycritic-2.9.3 vs Rakefile in rubycritic-2.9.4

@@ -1,4 +1,5 @@
+# frozen_string_literal: true
 require 'bundler/gem_tasks'
 require 'rake/testtask'
 require 'rubocop/rake_task'
 require 'cucumber/rake/task'
 require 'reek/rake/task'