chore(package): update babel-preset-airbnb to version 4.2.0

Closes #35

Author: greenkeeper[bot]

package.json

@@ -41,7 +41,7 @@
   "devDependencies": {
     "airbnb-js-shims": "^1.3.0",
     "babel-cli": "^6.26.0",
-    "babel-preset-airbnb": "^2.4.0",
+    "babel-preset-airbnb": "^4.2.0",
     "babel-register": "^6.26.0",
     "chai": "^4.1.2",
     "eslint": "^4.10.0",