Restore netstandard2.0 target

[asherber]

It would be helpful to put back the netstandard2.0 target, so that projects which do not yet target net8.0 can continue to benefit from bug fixes and new features.

The solution compiles just fine for netstandard2.0, since there are no net8.0-specific methods in use.

[ahmad-moussawi]

@asherber I understand the need here, but I won't be locked in an unsupported version .net, even if currently it has no compile issues, but it might refrain us from using new features in .net.

Another option could be to release a stable (3.x) version that supports old .net version

[asherber]

Technically, .NET Standard isn't a version of .NET -- it's an API specification which is supported by multiple runtimes (.NET Core 2.0+, .NET Framework 4.6.1+, .NET 5+). The usual advice for libraries is to stick with the lowest version that you can -- until you need new functionality that only a newer runtime provides.

I maintain several applications which use the .NET Framework -- which is still supported on current versions of Windows -- and without a .NET Standard target, I won't be able to upgrade this library. The same is true of people using .NET 6 and 7, which are also still supported.