.NET Core 2.1 introduced some runtime changes to support Span<T> and ByReference. Along with this comes the ability to do things like reinterpret memory as a different type. In .NET Framework the garbage collector couldn't track these references. These features proved useful enough that support for .NET Framework was dropped.
* Target netstandard2.1 and netcoreapp3.0
* Build: Zip native builds. Put version in zip filename
* Always build native exe on AppVeyor
- Make generated NuGet packages deterministic.
- Add a signing option to the build script.
- Set versions for pre-release builds.
- Publish packages to a MyGet feed.
- Make Windows-produced artifacts match Linux-produced ones