Add support for .NetStandard 2.0

[ehtick]

The older version 5.22 supported .NetStandard 2.0, would be great that the newer version would do this also.
Stil using .NetStandard 2.0 because the usage in older .net classic and newer .net 8.0

[felovala]

Look at #3115 :-)

[paulmedynski]

Hi @ehtick - support for .NET Standard was dropped with the 6.0 release.

The original issue and discussion are here: #2340

An ongoing Discussion topic is here: #3115

Please add to that discussion if you have any specific use cases that aren't met given the suggestions found therein.