chore(package): update eslint to version 5.15.1

Closes #13

Author: greenkeeper[bot]

package.json

@@ -75,7 +75,7 @@
     "css-loader": "^0.28.7",
     "enzyme": "^3.3.0",
     "enzyme-adapter-react-16": "^1.1.1",
-    "eslint": "^4.14.0",
+    "eslint": "^5.15.1",
     "eslint-plugin-babel": "^4.1.2",
     "eslint-plugin-react": "^7.5.1",
     "extract-text-webpack-plugin": "^3.0.2",