.rubocop.yml in polyfill-0.6.0 vs .rubocop.yml in polyfill-0.7.0

@@ -1,6 +1,6 @@
 AllCops:
-  TargetRubyVersion: 2.2
+  TargetRubyVersion: 2.1
 Metrics/AbcSize:
   Enabled: false
 Metrics/BlockLength:
   Enabled: false
 Metrics/CyclomaticComplexity: