Update appveyor.yml

appveyor.yml

@@ -14,4 +14,4 @@ build:
   verbosity: minimal
 test_script:
 - cmd: dotnet vstest "%APPVEYOR_BUILD_FOLDER%\Tests\MQTTnet.Core.Tests\bin\Release\netcoreapp2.1\MQTTnet.Core.Tests.dll"
-- cmd: dotnet vstest "%APPVEYOR_BUILD_FOLDER%\Tests\MQTTnet.TestApp.AspNetCore2\bin\Release\netcoreapp2.1\MQTTnet.TestApp.AspNetCore2.dll"
+- cmd: dotnet vstest "%APPVEYOR_BUILD_FOLDER%\Tests\MQTTnet.TestApp.AspNetCore\bin\Release\netcoreapp2.1\MQTTnet.TestApp.AspNetCore.dll"