chore(package): update eslint to version 5.15.3

Closes #119

Author: greenkeeper[bot]

package.json

@@ -38,7 +38,7 @@
     "babel-plugin-transform-object-rest-spread": "^6.6.5",
     "babel-preset-es2015": "^6.6.0",
     "bluebird": "^3.3.4",
-    "eslint": "^4.8.0",
+    "eslint": "^5.15.3",
     "eslint-config-airbnb": "^16.0.0",
     "eslint-import-resolver-webpack": "^0.8.3",
     "eslint-plugin-import": "^2.7.0",