Bring back .NET Standard 2.0 for Microsoft.Data.SqlClient

[ehavelaarsnz]

Description

I have a .NET Standard 2.0 class library which references Microsoft.Data.SqlClient 5.2.2
If I upgrade it to Microsoft.Data.SqlClient 6.0.1, I get the build warning, NU1701:

Package 'Microsoft.Data.SqlClient.SNI 6.0.2' 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, .NETFramework,Version=v4.8.1' instead of the project target framework '.NETStandard,Version=v2.0'. This package may not be fully compatible with your project.

What I'd like

I'd like a dependency on .NET Standard to be declare in Microsoft.Data.SqlClient 6.0.1 as it was in version 5.2.2. The .NET Framework 4.6.2 one is still there, so I don't see why the .NET Standard one needs to disappear.

[MichelZ]

This is a duplicate of #3157
See these related things:

Original Issue: #2340
Original PR: #2386

Discussion Thread: #3115