chore(package): update eslint to version 6.2.1

Closes #77

Author: greenkeeper[bot]

package.json

@@ -25,7 +25,7 @@
     "babel-register": "^6.26.0",
     "chai": "^4.1.1",
     "chai-things": "^0.2.0",
-    "eslint": "^4.6.0",
+    "eslint": "^6.2.1",
     "eslint-config-airbnb-base": "^12.0.0",
     "eslint-plugin-import": "^2.7.0",
     "mocha": "^5.0.0"