test(NLU): Skip list_models integration test. Covered by unit test

Author: maxnussbaum

test/integration/test_natural_language_understanding_v1.rb

@@ -82,6 +82,7 @@ def test_url_analyze
     end
 
     def test_list_models
+      skip
       service = IBMWatson::NaturalLanguageUnderstandingV1.new(
         version: "2018-03-16",
         username: ENV["NATURAL_LANGUAGE_UNDERSTANDING_USERNAME"],