Update appveyor.yml

Author: unitycoder

appveyor.yml

@@ -14,9 +14,9 @@ before_build:
 after_build:
 - cmd: 7z a PixelArtTool.zip %APPVEYOR_BUILD_FOLDER%\PixelArtTool\bin\Release\*.exe %APPVEYOR_BUILD_FOLDER%\PixelArtTool\bin\Release\*.exe.config
 - cmd: candle -nologo -out %APPVEYOR_BUILD_FOLDER%\PixelArtTool.wixobj %APPVEYOR_BUILD_FOLDER%\PixelArtTool\Installer.wxs
-  working_directory: %APPVEYOR_BUILD_FOLDER%
+  working_directory: "%APPVEYOR_BUILD_FOLDER%"
 - cmd: light -nologo -out %APPVEYOR_BUILD_FOLDER%\PixelArtTool.msi %APPVEYOR_BUILD_FOLDER%\PixelArtTool.wixobj
-  working_directory: %APPVEYOR_BUILD_FOLDER%
+  working_directory: "%APPVEYOR_BUILD_FOLDER%"
 - cmd: copy %APPVEYOR_BUILD_FOLDER%\PixelArtTool.msi %APPVEYOR_BUILD_FOLDER%\PixelArtTool\bin\Release
 artifacts:
 - path: PixelArtTool.zip