chore(package): update eslint to version 5.15.0

Closes #8

Author: greenkeeper[bot]

package.json

@@ -32,7 +32,7 @@
   "devDependencies": {
     "babel-cli": "^6.26.0",
     "babel-preset-es2015": "^6.24.1",
-    "eslint": "^5.0.0",
+    "eslint": "^5.15.0",
     "mocha": "^5.2.0",
     "should": "^13.2.1"
   }