* Target .NET Core 3.0 * Update build and test project packages * Update AppVeyor build image
* Use .NET Framework reference assemblies from NuGet * Update build packages. Specify --no-build when publishing * Don't sign on Linux
- 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