chore(package): update eslint to version 4.15.0 (#44)

Author: greenkeeper[bot]

package.json

@@ -42,7 +42,7 @@
     "emoji-js": "^3.2.2",
     "enzyme": "^3.2.0",
     "enzyme-adapter-react-16": "^1.1.1",
-    "eslint": "4.14.0",
+    "eslint": "4.15.0",
     "eslint-plugin-react": "^7.5.1",
     "extract-text-webpack-plugin": "^3.0.2",
     "ignore-styles": "^5.0.1",