fix(readme): update doc (starter kit) link (#1770)

Author: crissty

README.md

@@ -51,7 +51,7 @@ And many more!
 <a target="_blank" href="http://akveo.com/ngx-admin/">Live Demo</a>
 
 ## Documentation
-This template is using [Nebular](https://github.com/akveo/nebular) modules set, [here you can find documentation and other useful articles](https://akveo.github.io/nebular/docs/installation/based-on-starter-kit-ngxadmin).
+This template is using [Nebular](https://github.com/akveo/nebular) modules set, [here you can find documentation and other useful articles](https://akveo.github.io/nebular/docs/guides/install-based-on-starter-kit).
 
 ### ng2-admin
 We will continue supporting [ng2-admin](https://github.com/akveo/ngx-admin/tree/ng2-admin) version, but if you are starting from scratch we recommend using `ngx-admin`. Unfortunately, there is no way to automatically update from ng2-admin to ngx-admin, but some parts (Nebular components) could be manually included.