Fixes rubocop issue with Zing JRE framework

Author: David O'Sullivan

lib/java_buildpack/jre/zing_jre.rb

@@ -26,6 +26,7 @@ module Jre
     class ZingJRE < OpenJDKLike
       # (see JavaBuildpack::Component::ModularComponent#command)
       def command
+        # no command
       end
 
       # (see JavaBuildpack::Component::ModularComponent#sub_components)