chore(package): update babel-preset-es2015 to version 6.13.1 (#1103)

https://greenkeeper.io/

package.json

@@ -12,7 +12,7 @@
     "babel": "~6.5.2",
     "babel-core": "~6.10.4",
     "babel-loader": "~6.2.4",
-    "babel-preset-es2015": "~6.9.0",
+    "babel-preset-es2015": "~6.13.1",
     "babelify": "~7.3.0",
     "bower": "~1.7.9",
     "browser-sync": "~2.14.0",