docs(tutorial): npm needs "run" keyword for custom script names

Fix "npm run update-webdriver" command

Closes #7071

Author: rspeicher

docs/content/tutorial/index.ngdoc

@@ -134,7 +134,7 @@ tasks that you will need while developing:
 - `npm start` : start a local development web-server
 - `npm test` : start the Karma unit test runner
 - `npm run protractor` : run the Protractor end 2 end tests
-- `npm update-webdriver` : install the drivers needed by Protractor
+- `npm run update-webdriver` : install the drivers needed by Protractor
 
 ### Running Development Web Server
 
@@ -233,4 +233,4 @@ before pushing a new commit of changes to a remote repository.
 [protractor]: https://github.com/angular/protractor
 [bower]: http://bower.io/
 [http-server]: https://github.com/nodeapps/http-server
-[karma]: https://github.com/karma-runner/karma
+[karma]: https://github.com/karma-runner/karma