chore(package): update eslint to version 6.2.1

Closes #29

Author: greenkeeper[bot]

package.json

@@ -33,7 +33,7 @@
     "babel-plugin-add-module-exports": "^0.2.1",
     "babel-preset-env": "^1.3.2",
     "babel-register": "^6.24.1",
-    "eslint": "^4.5.0",
+    "eslint": "^6.2.1",
     "eslint-config-prev": "^6.0.0",
     "jsdom": "^9.12.0",
     "rimraf": "^2.6.1",