Update @types/node and typescript dependency (#737)

The new version of @types/node avoids the new generator types introduced
recently in typescript@next.

Author: sandersn

package-lock.json

@@ -11,7 +11,7 @@
   },
   "dependencies": {
     "@types/jsdom": "^11.0.4",
-    "@types/node": "^9.4.6",
+    "@types/node": "^9.6.49",
     "@types/node-fetch": "^1.6.7",
     "@types/webidl2": "^10.2.1",
     "cpx": "^1.5.0",