Update to latest Nugets and .NET 8

[xantari]

Motivation

This project should be updated to .NET 8 and the latest nugets.

There are breaking changes that this project does not address such as this: kontent-ai/delivery-sdk-net#390

Proposed solution

Update solution to .NET 8 and latest nugets.

[pokornyd]

Hello Xantari, thank you for your submission.

while this boilerplate is indeed outdated, we're yet to discuss the future of .NET samples. both an update to the existing ones and a creation of new set of samples are an option at the moment.

I'll make sure to update you as we progress with the decision, though I'm not able to provide any estimates yet. thank you for your patience.

[xantari]

Sounds good, yeah maybe a new sample is better, with a link on the "old" boiler plate that says for a newer version go here or something. That way folks who are still using the old stuff can reference the old boiler plate.

[michaelddiworld]

+1 this idea

[anthony-sams]

+1 this idea