Merge pull request #227 from javascript-obfuscator/target-es2017

Changed `target` on `es2017`

.babelrc

@@ -5,7 +5,7 @@
   "presets": [
     ["@babel/preset-env", {
       "targets": {
-        "node": "4.8"
+        "node": "6.11"
       },
       "forceAllTransforms": true
     }]

tsconfig.json

@@ -15,7 +15,7 @@
     "removeComments": true,
     "sourceMap": true,
     "strict": true,
-    "target": "es2015",
+    "target": "es2017",
     "plugins": [
       {
         "name": "tslint-language-service",