Bump rubocop up to newer ruby versions (in progress)

auto/colour_reporter.rb

@@ -12,7 +12,7 @@ def report(message)
   if !$colour_output
     $stdout.puts(message)
   else
-    message = message.join('\n') if message.class == Array
+    message = message.join('\n') if message.instance_of?(Array)
     message.each_line do |line|
       line.chomp!
       colour = case line