chore(package): update eslint to version 5.15.2

Closes #52

Author: greenkeeper[bot]

package.json

@@ -49,7 +49,7 @@
     "chokidar": "^2.0.0",
     "codecov.io": "^0.1.6",
     "contributor-faces": "^1.0.0",
-    "eslint": "^4.9.0",
+    "eslint": "^5.15.2",
     "eslint-config-ngryman": "^1.7.0",
     "nyc": "^11.2.1",
     "pre-commit": "^1.1.2",