Fix appveyor

Author: Jimmy Byrd

appveyor.yml

@@ -4,8 +4,7 @@ build_script:
   - cmd: build.cmd
 test: off
 version: 0.0.1.{build}
-install:
-  - cmd: choco install dotnetcore-sdk -y
+image: Visual Studio 2019 Preview
 artifacts:
   - path: bin
     name: bin