[npm] update js-yaml dependency

major version bump did not break our usage, drop in replacement seems to work, fixes a bug we were having

package.json

@@ -68,7 +68,7 @@
     "grunt-s3": "~0.2.0-alpha.3",
     "grunt-saucelabs": "~8.2.0",
     "jquery": "~2.1.1",
-    "js-yaml": "~2.1.3",
+    "js-yaml": "^3.6.0",
     "load-grunt-config": "~0.7.0",
     "load-grunt-tasks": "~0.2.0",
     "mocha": "^2.2.5",
@@ -104,4 +104,4 @@
   "engines": {
     "node": ">=0.8"
   }
-}
+}