Update tslint to fix js-yaml vulnerability

Author: ulvesked

src/package-lock.json

@@ -49,7 +49,7 @@
         "semver": "^5.5.0",
         "tns-core-modules": "^4.2.0",
         "tns-platform-declarations": "^4.2.1",
-        "tslint": "^5.11.0",
+        "tslint": ">=5.18.0",
         "typescript": "~2.8.2"
     },
     "dependencies": {},