chore(package): update eslint to version 6.8.0

Closes #4

Author: greenkeeper[bot]

package.json

@@ -17,7 +17,7 @@
     "nyc": "^11.2.1"
   },
   "devDependencies": {
-    "eslint": "^4.9.0",
+    "eslint": "^6.8.0",
     "husky": "^0.14.3"
   },
   "directories": {