Exception when targeting .NET Framework with .NET 7 installed

[ilnarag]

With .NET 7 installed, targeting .NET Framework throws an exception on a test run.
This issue was already fixed:

• Exception when targeting .NET Framework with .NET 7 installed nunit-console#1176
• System.ArgumentException: Unknown framework version 7.0 nunit3-vs-adapter#987

According to the release notes, the NUnit3TestAdapter package needs to be updated to version 4.3.0 to make things work.