Rakefile in nanoc-4.7.9 vs Rakefile in nanoc-4.7.10

@@ -1,4 +1,6 @@
+# frozen_string_literal: true
+
 require 'rubocop/rake_task'
 require 'rspec/core/rake_task'
 require 'rake/testtask'
 require 'coveralls/rake/task'