.rubocop.yml in cose-0.10.0 vs .rubocop.yml in cose-0.11.0

@@ -4,10 +4,10 @@
 inherit_mode:
   merge:
     - Exclude
 
 AllCops:
-  TargetRubyVersion: 2.3
+  TargetRubyVersion: 2.4
   DisabledByDefault: true
   Exclude:
     - "gemfiles/**/*"
 
 Bundler: