.rubocop.yml in gistory-0.3.0 vs .rubocop.yml in gistory-0.4.0

@@ -1,5 +1,7 @@
-require: rubocop-rspec
+require:
+  - rubocop-rspec
+  - rubocop-performance
 
 AllCops:
   TargetRubyVersion: 2.4
   NewCops: enable