chore(package): update @types/node to version 11.9.1

Closes #5

Author: greenkeeper[bot]

package.json

@@ -80,7 +80,7 @@
   },
   "devDependencies": {
     "@types/jest": "^23.3.10",
-    "@types/node": "^10.12.15",
+    "@types/node": "^11.9.1",
     "colors": "^1.1.2",
     "commitizen": "^3.0.5",
     "coveralls": "^3.0.2",