chore(package): update eslint to version 6.7.0

Closes #30

Author: greenkeeper[bot]

package.json

@@ -28,7 +28,7 @@
   "dependencies": {},
   "devDependencies": {
     "chai": "^3.5.0",
-    "eslint": "^3.12.2",
+    "eslint": "^6.7.0",
     "eslint-config-fullstack": "^3.0.0",
     "eslint-plugin-react": "^7.0.0",
     "husky": "^0.13.0",