chore: update generated app tsconfig to enable es2016 apis (#4474)

Author: delasteve

packages/@angular/cli/blueprints/ng2/files/__path__/tsconfig.json

@@ -5,7 +5,7 @@
     "emitDecoratorMetadata": true,
     "experimentalDecorators": true,
     "lib": [
-      "es2015",
+      "es2016",
       "dom"
     ],
     "mapRoot": "./",