How to resolve?
Package 'GoogleAuthenticator 1.2.1' was restored using '.NETFramework,Version=v4.6.1, .NETFramework,Version=v4.6.2, .NETFramework,Version=v4.7, .NETFramework,Version=v4.7.1, .NETFramework,Version=v4.7.2, .NETFramework,Version=v4.8' instead of the project target framework '.NETCoreApp,Version=v2.1'. This package may not be fully compatible with your project.
But I don't want to upgrade to latest version (C#)
