Support the Newer Versions of the .NET Runtime

[tsutomi]

The current framework is implemented on top of the .NET 6.0 framework, which has been put on Long Term Support (LTS) by Microsoft, the first phase in the process of retirement.

We should aim to add support for the .NET 7.0 and potentially the .NET 8.0 frameworks, to make the Deveel Webhooks future-proof.

Expected Benefits

The newer versions of the .NET framework improve the performances of several of the low-level components, resulting in improved performances of the applications.

Even not rewriting the code of the Deveel Webhooks framework, to use the latest constructs of the .NET, we might benefit by providing assemblies that are built against the newer versions of the .NET framework.

Possible Side Effects