Fix rubocop warning.

Author: fnando

Diff for: lib/i18n-js/cli/command.rb

@@ -21,8 +21,8 @@ def self.parse(&block)
         end
       end
 
-      def self.command(&block)
-        define_method(:command, &block)
+      def self.command(&)
+        define_method(:command, &)
       end
 
       def initialize(argv:, ui:)