chore(package): update eslint to version 5.15.0

Closes #39

Author: greenkeeper[bot]

package.json

@@ -41,7 +41,7 @@
   "devDependencies": {
     "browser-sync": "^2.18.8",
     "babel-eslint": "^8.2.2",
-    "eslint": "^4.1.1",
+    "eslint": "^5.15.0",
     "eslint-plugin-ava": "^4.2.1",
     "eslint-plugin-import": "^2.6.1",
     "eslint-plugin-itgalaxy": "^66.0.0",