.rubocop.yml in slackit-1.1.8 vs .rubocop.yml in slackit-1.1.10

- old
+ new

@@ -1,4 +1,7 @@
+AllCops:
+  TargetRubyVersion: 2.5
+
 Layout/CaseIndentation:
     Enabled: false
 
 Layout/ClosingHeredocIndentation:
     Enabled: false