Merge pull request #58 from LeetCode-OpenSource/greenkeeper/standard-13.0.1

Update standard to the latest version 🚀

Author: Brooooooklyn

package.json

@@ -42,7 +42,7 @@
     "rxjs": "^6.5.2",
     "sinon": "^7.3.2",
     "source-map-loader": "^0.2.4",
-    "standard": "^12.0.1",
+    "standard": "^13.0.1",
     "ts-jest": "^24.0.2",
     "ts-loader": "^6.0.2",
     "tslint": "^5.17.0",