chore(package): update eslint to version 6.8.0

Closes #39

Author: greenkeeper[bot]

package.json

@@ -15,7 +15,7 @@
   "devDependencies": {
     "babel-cli": "^6.0.0",
     "babel-preset-env" : "^1.6.1",
-    "eslint": "^5.0.0",
+    "eslint": "^6.8.0",
     "mocha": "^5.0.0",
     "mocha": "^5.0.0",
     "mocha-junit-reporter": "^1.15.0"