Update appveyor.yml

Wrap full commands for netstandard tests in quotes

Author: jimschubert

appveyor.yml

@@ -42,8 +42,8 @@ test_script:
   # restore test-related files
   - copy /b/v/y CI\samples.ci\client\petstore\csharp\OpenAPIClient\src\Org.OpenAPITools.Test\Org.OpenAPITools.Test.csproj samples\client\petstore\csharp\OpenAPIClient\src\Org.OpenAPITools.Test\Org.OpenAPITools.Test.csproj
   # test c# API client (refactor)
-  - '%xunit20%\xunit.console' samples\client\petstore\csharp-refactor\OpenAPIClient\src\Org.OpenAPITools.Test\bin\Debug\netcoreapp2.0\Org.OpenAPITools.Test.dll /appveyor
-  - '%xunit20%\xunit.console' samples\client\petstore\csharp-refactor\OpenAPIClientCore\src\Org.OpenAPITools.Test\bin\Debug\netcoreapp2.0\Org.OpenAPITools.Test.dll /appveyor
+  - '%xunit20%\xunit.console samples\client\petstore\csharp-refactor\OpenAPIClient\src\Org.OpenAPITools.Test\bin\Debug\netcoreapp2.0\Org.OpenAPITools.Test.dll -appveyor'
+  - '%xunit20%\xunit.console samples\client\petstore\csharp-refactor\OpenAPIClientCore\src\Org.OpenAPITools.Test\bin\Debug\netcoreapp2.0\Org.OpenAPITools.Test.dll -appveyor'
   # test c# API client
   - nunit-console samples\client\petstore\csharp\OpenAPIClient\src\Org.OpenAPITools.Test\bin\Debug\Org.OpenAPITools.Test.dll --result=myresults.xml;format=AppVeyor
   # test c# API client (with PropertyChanged)