chore(package): update babel-core to version 6.22.0

https://greenkeeper.io/

Author: greenkeeper[bot]

package.json

@@ -52,7 +52,7 @@
   "devDependencies": {
     "ava": "^0.18.1",
     "babel-cli": "^6.16.0",
-    "babel-core": "^6.17.0",
+    "babel-core": "^6.22.0",
     "babel-eslint": "^7.0.0",
     "babel-polyfill": "^6.16.0",
     "babel-preset-es2015": "^6.16.0",