Update known frameworks to test against

[ViktorHofer]

To double check:

• The right tests are in and and the right validation has happened. Guidance: https://github.com/dotnet/core-eng/tree/master/Documentation/Validation

Removing net463 and net46 as these newer shipped a targeting pack and these tfms are already disabled in dotnet/runtime's package validation.

Removing tfms that aren't supported in dotnet/runtime anymore.

[ViktorHofer]

@Anipik looks like netcoreapp3.1 isn't chosen because it isn't the min version and netcoreapp2.0 isn't in the list. Is that assumption right? If yes, what would need to change to choose the minimum supported .NETCoreApp version based on our support policy and not based on the netstandard compatibility matrix?

[Anipik]

Will take a look at the failures here later today.

[ViktorHofer]

thanks 👍

[Anipik]

#7510

@ViktorHofer we can close this one. the tests and code here has drastically changed.