chore(package): update eslint to version 4.7.0

Closes #15

Author: greenkeeper[bot]

package.json

@@ -17,7 +17,7 @@
     "babel-cli": "^6.18.0",
     "babel-preset-env": "^1.3.3",
     "coveralls": "^2.11.15",
-    "eslint": "^3.15.0",
+    "eslint": "^4.7.0",
     "eslint-config-airbnb": "^14.1.0",
     "eslint-plugin-import": "^2.2.0",
     "eslint-plugin-jsx-a11y": "^3.0.2 || ^4.0.0",