I tried to create a project for cardboard VR. I imported the git VR package from this path Click here to download VR GITHUB Path, Then in Project settings -> XR Plug-in Management I tried to check Cardboard XB Plugin, The package is not installed, I got the error message which is shown in the below screenshot.

Please tell me how to fix this issue
Error Message:
XR Plug-in Managfement error. Failure reason: Error Message: Unable to add package [com.google.xr.cardboard]: Package [com.google.xr.cardboard] cannot be found. Error installing package com.google.xr.cardboard.. check if there are any other in the console and make sure they are connected before trying again. UnityEditor.EditorApplication:Internal_CallUpdateFunction()
Thanks in Advance.