Support for .NET 8 environment

[lcsoft77]

Hi, I’ve created a Fission environment for .NET 8.0 and published it here: https://github.com/lcsoft77/fission-env-dotnet8

Would it be possible to add official support for .NET 8? I can submit a PR if needed. Let me know what you think!

Thanks!

[sanketsudake]

@lcsoft77 Please raise PR to environments. Me and @soharab-ic will help in getting it merged and for publishing environment through our fission pipeline