chore(package): update eslint to version 6.8.0

Closes #3

Author: greenkeeper[bot]

package.json

@@ -15,7 +15,7 @@
     "node-notifier": "^5.2.1"
   },
   "devDependencies": {
-    "eslint": "^4.19.1",
+    "eslint": "^6.8.0",
     "eslint-config-google": "^0.9.1"
   }
 }