chore(package): update eslint to version 6.2.0

Closes #22

Author: greenkeeper[bot]

package.json

@@ -49,7 +49,7 @@
     "chai": "^4.0.0-canary.1",
     "coveralls": "^3.0.3",
     "del": "^3.0.0",
-    "eslint": "^4.9.0",
+    "eslint": "^6.2.0",
     "eslint-config-airbnb-base": "^12.1.0",
     "eslint-plugin-import": "^2.9.0",
     "istanbul": "^1.1.0-alpha.1",