Wait. It worked???

.ci/windows-steps.yaml

@@ -191,7 +191,7 @@ steps:
   displayName: 'Publish artifacts test results'
 - task: PublishBuildArtifacts@1
   inputs:
-    pathtoPublish: 'dist\win-installer\mlpack-win-installer\bin\x64\Release\*.msi'
+    pathtoPublish: 'dist\win-installer\mlpack-win-installer\bin\Release\*.msi'
     artifactName: mlpack-windows-installer
   displayName: 'Publish Windows MSI installer'
 

dist/win-installer/mlpack-win-installer/mlpack-win-installer.wixproj

@@ -12,7 +12,6 @@
     <DefineSolutionProperties>false</DefineSolutionProperties>
     <DefineConstants>SourceDir=.\Sources</DefineConstants>
     <WixTargetsPath Condition=" '$(WixTargetsPath' == '' ">$(MSBuildExtensionsPath)\Microsoft\WiX\v3.x\Wix.targets</WixTargetsPath>
-    <VerboseOutput>true</VerboseOutput>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|x86' ">
     <OutputPath>bin\$(Configuration)\</OutputPath>