.rubocop.yml in mistral_client-1.2.1 vs .rubocop.yml in mistral_client-1.3.0

@@ -1,4 +1,7 @@
+AllCops:
+  TargetRubyVersion: 2.3
+
 Style/Documentation:
   Enabled: false
 
 Style/FrozenStringLiteralComment:
   Enabled: false