Update dependency uglify-js to v3.19.2

Author: renovate[bot]

package.json

@@ -33,7 +33,7 @@
     "rquery": "2.0.9",
     "sinon": "1.17.7",
     "sinon-chai": "2.14.0",
-    "uglify-js": "3.4.4"
+    "uglify-js": "3.19.2"
   },
   "scripts": {
     "test": "karma start karma.conf.js",