Update appveyor.yml

appveyor.yml

@@ -1,4 +1,4 @@
-os: Previous Visual Studio 2017
+os: Visual Studio 2017
 platform:
 - Any CPU
 skip_branch_with_pr: true
@@ -22,7 +22,7 @@ install:
 before_build:
 - git submodule update --init
 build_script:
-- ps: .\build.ps1 -Target "AppVeyor" -Platform "$env:platform" -Configuration "$env:configuration"
+- ps: .\build.ps1 -Target "AppVeyor" -Platform "$env:platform" -Configuration "$env:configuration" -v Diagnostic
 
 test: off
 artifacts: