Use a Source Generator to extract the Version information

[andreaTP]

Ref: microsoft/kiota#2149 (comment) by @baywet

Opening as Draft as I'm not sure if the extracted version is the desired one(haven't checked).

Also, since we are re-using almost the same code it might be worth exploring how to make this Source Generator generic enough and publish it as a NuGet package, I think there are two improvements required:

• if a file .csproj doesn't exist in the directory containing the mainSyntaxTree explore the Parent until you find one
• Export the entire .csproj content, possibly generating the fluent API to programmatically access the elements

[baywet]

Thanks for fixing that!

[andreaTP]

if this is good enough for you, happy to move forward 🙂