refactor(package): add missing update-deps script

This script might be useful to tutorial users (e.g. for upgrading
AngularJS or Protractor).

Author: gkalpak

package.json

@@ -22,6 +22,8 @@
   },
   "scripts": {
     "postinstall": "npm run copy-libs",
+    "update-deps": "npm update",
+    "postupdate-deps": "npm run copy-libs",
     "copy-libs": "cpx \"node_modules/{angular,angular-*,bootstrap/dist}/**/*\" app/lib -C",
     "prestart": "npm install",
     "start": "http-server ./app -a localhost -p 8000 -c-1",