chore(package): update babel-preset-es2015 to version 6.9.0 (#746)

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -11,7 +11,7 @@
     "babel": "~6.5.2",
     "babel-core": "~6.9.0",
     "babel-loader": "~6.2.0",
-    "babel-preset-es2015": "~6.6.0",
+    "babel-preset-es2015": "~6.9.0",
     "babelify": "~7.3.0",
     "bower": "~1.7.1",
     "browser-sync": "~2.12.1",