Add netcoreapp target

[Liklainy]

• Changed to sdk style
• Added netcoreapp targets
• Merged nuspec props to csproj
• Changed tasks.py to update version in csproj
• Changed to dotnet build and pack in azure-pipelines

[kenjiuno]

Thanks i'll test this

[Liklainy]

Sorry, It seems I have broken your pipeline 😔 Do I need to update tests too?

[kenjiuno]

@Liklainy Thanks for looking at this. I have some ideas and I'll test it first. I'll let you know if I need helps about .NET Core part!

[kenjiuno]

Thanks, I have merged your changes with fixing tests. Now published at nuget:

kenjiuno.PdfSharp-WPF 1.31.5584
kenjiuno.PdfSharp.Xps 1.1.6

[Liklainy]

👍 Great! 😄 Thank you, you’re amazing!