chore(package): update eslint to version 6.0.0

Closes #11

Author: greenkeeper[bot]

package.json

@@ -15,7 +15,7 @@
     "babel-core": "^6.26.0",
     "babel-jest": "^21.2.0",
     "babel-preset-env": "^1.6.1",
-    "eslint": "^4.11.0",
+    "eslint": "^6.0.0",
     "jest": "^21.2.1",
     "prettier": "^1.8.2"
   },