Update to .NET 7.0 #106
Description
Unfortunately it looks like there's a problem with multi-targeting net6.0 and net7.0 because of a feature that switched from experimental to non-experimental. The .NET 7 SDK can build .NET 6 code, but it says that LangVersion must be 11 and ExperimentalFeatures must be True, but setting them as commanded does not clear the build error.
Therefore, 9.0 will drop support for 6.0; any bugs that arise can be addressed in 8.x and 9.x builds.
Avoid the Experiemental features flag in the future. It was worth it, this time.