Add new Windows PE tags for license

### Description
In this question by @suterma https://opensource.stackexchange.com/a/8874/947 @andxpto points to recent license-related tag addition in Windows assemblies that we do not yet collect in https://github.com/nexB/scancode-toolkit/blob/450205506989607c8361b17e1bce0db63c9923b2/src/packagedcode/win_pe.py#L73

See https://docs.microsoft.com/en-us/dotnet/core/tools/csproj#packagelicensefile

These would be likely be primarily in NuGet/nuspec but may also land in PE metadata (though I could not verify this). We should check if these assembly tags end up in the built DLL or not and collect them if so. And make sure we get them in nuspecs.