chore(package): update ts-node to version 8.1.1

Closes #44

Author: greenkeeper[bot]

package.json

@@ -32,7 +32,7 @@
     "nsp": "^3.1.0",
     "supertest": "^3.3.0",
     "ts-jest": "^23.10.4",
-    "ts-node": "^7.0.1",
+    "ts-node": "^8.1.1",
     "tslint": "^5.11.0",
     "typescript": "^3.1.6"
   },