chore(package): Switch to show_changelog for npm run changelog

Author: christopherthielen

package.json

@@ -21,7 +21,7 @@
     "watch:dts-downlevel": "npm run fixdts",
     "watch:test": "karma start --singleRun=false --autoWatch=true --autoWatchInterval=1",
     "debug": "karma start --singleRun=false --autoWatch=true --autoWatchInterval=1 --browsers=ChromeCanary",
-    "changelog": "update_changelog",
+    "changelog": "show_changelog",
     "release": "release"
   },
   "homepage": "https://ui-router.github.io",