updated yargs

Author: sylouuu

package.json

@@ -31,6 +31,6 @@
         "karma-phantomjs-launcher": "~1.0.0",
         "karma-spec-reporter": "~0.0.20",
         "phantomjs-prebuilt": "~2.1.0",
-        "yargs": "~4.1.0"
+        "yargs": "~4.2.0"
     }
 }