#30 Update for .Net 9.0

[saper-2]

Hi,

I'm building app ("what I don't say" 😅 ) , and I switched for .Net 9.0 (why not to go for latest version 😎) , BUT unfortunately last release 2.9.1 is only build for NetFramework 4.x (and std. 2.0), so It won't work with net 9.

I tried to grab code, tinker with csproj file to bump up net build version, but it didn't work :-/ . There is some code that using something that not exists in net 9 (since net 6+ if I remember).
And, I'm coding in C# 😀