config_validator.rb in leftovers-0.6.0

- old
+ new

@@ -1,6 +1,7 @@
 # frozen-string-literal: true
 
+require 'set'
 require 'json_schemer'
 
 module Leftovers
   module ConfigValidator
     autoload(:ErrorProcessor, "#{__dir__}/config_validator/error_processor")