Update dependency eslint-config-airbnb to v18 (#493)

Author: renovate[bot]

package-lock.json

@@ -41,7 +41,7 @@
     "chromedriver": "75.1.0",
     "del": "5.1.0",
     "eslint": "6.1.0",
-    "eslint-config-airbnb": "17.1.1",
+    "eslint-config-airbnb": "18.0.1",
     "eslint-plugin-import": "2.18.2",
     "geckodriver": "1.16.2",
     "istanbul": "0.4.5",