chore(package): update eslint-config-airbnb to version 18.1.0

Closes #44

Author: greenkeeper[bot]

package.json

@@ -51,7 +51,7 @@
     "babel-eslint": "^10.0.1",
     "babel-minify": "^0.5.0",
     "eslint": "^5.12.0",
-    "eslint-config-airbnb": "^17.1.0",
+    "eslint-config-airbnb": "^18.1.0",
     "eslint-config-prettier": "^3.3.0",
     "eslint-plugin-import": "^2.14.0",
     "eslint-plugin-prettier": "^3.0.1",