Add dotnet 8 support

[Goltom]

• Add support for .net8
• IPNetwork renamed to IPNetwork2
• Update nuget package Microsoft.NET.Test.Sdk
• Unittest fix

[coveralls]

Pull Request Test Coverage Report for Build 624

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 94.615%

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Totals
Change from base Build 618:	0.0%
Covered Lines:	1599
Relevant Lines:	1690

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💛 - Coveralls

[lduchosal]

Well, everyone tracking ipnetwork nuget will get its build broken:

• This should be upgrade a new major versionv 3.0.0
• Documentation (README.md) should be modifed accordingly
• Automatic Build should be upgraded to use net8
• Test units and code coverage must pass

[lduchosal]

Thanks for you help

[Maxwell175]

@lduchosal The better solution should have been to move everything out of the System namespace entirely. Because it is intended to only be used by Microsoft. Otherwise we are just waiting for Microsoft to add their own IPNetwork2 and then we have the same issue once again.

[lduchosal]

Sure, PR welcome ! @Maxwell175

[Goltom]

Thanks for you help

You are welcome :)