chore(package): update babel-preset-es2015 to version 6.18.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -71,7 +71,7 @@
     "babel-cli": "^6.11.4",
     "babel-eslint": "^7.0.0",
     "babel-plugin-add-module-exports": "^0.2.1",
-    "babel-preset-es2015": "^6.9.0",
+    "babel-preset-es2015": "^6.18.0",
     "babel-preset-min": "^0.1.15",
     "babel-register": "^6.11.6",
     "coveralls": "^2.11.12",