chore(package): update eslint to version 5.15.1

Closes #8

Author: greenkeeper[bot]

package.json

@@ -19,7 +19,7 @@
     "resp-modifier": "^6.0.2"
   },
   "devDependencies": {
-    "eslint": "^4.1.1",
+    "eslint": "^5.15.1",
     "eslint-plugin-ava": "^4.2.1",
     "eslint-plugin-import": "^2.6.0",
     "eslint-plugin-itgalaxy": "^59.0.0",