chore(package): update eslint to version 6.7.1

Closes #34

Author: greenkeeper[bot]

package.json

@@ -14,7 +14,7 @@
   },
   "devDependencies": {
     "babel-eslint": "^10.0.1",
-    "eslint": "^5.0.1",
+    "eslint": "^6.7.1",
     "eslint-config-google": "^0.10.0",
     "eslint-plugin-flowtype": "^2.46.3",
     "eslint-plugin-import": "^2.11.0",