Merge pull request #429 from syuilo/greenkeeper/typescript-2.3.1

Update typescript to the latest version 🚀

package.json

@@ -145,7 +145,7 @@
     "tcp-port-used": "0.1.2",
     "textarea-caret": "3.0.2",
     "ts-node": "3.0.1",
-    "typescript": "2.2.2",
+    "typescript": "2.3.1",
     "uuid": "3.0.1",
     "vhost": "3.0.2",
     "websocket": "1.0.24",