fix(readme): update docks to point to the correct link for guestbook container image

Author: hidalz

README.md

@@ -50,7 +50,7 @@ a path in a Git repository automatically (e.g. using auto-sync).
    ```
 
    You will now have a `guestbook` container image repository. e.g.:
-   https://github.com/yourgithubusername/guestbook/pkgs/container/guestbook
+   https://github.com/users/yourgithubusername/packages/container/package/guestbook
 
 5. Change guestbook container image repository to public.