title: Azure DevOps yaml pipeline, downloaded artifact is empty
body: <p>Converting a pipeline from classic to YAML (so I know it works).</p>
  <p>I build and my publish artifact task looks like this:</p>
  <pre><code>  - task: PublishPipelineArtifact@1
      displayName: 'Publish Pipeline Artifact'
      inputs:
        targetPath: '$(Build.ArtifactStagingDirectory)/MyArtifact'
        artifact: MyArtifact
  </code></pre>
  <p>The result when build looks like this:</p>
  <p><a href="https://i.stack.imgur.com/DxKbr.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DxKbr.jpg" alt="enter image description here" /></a></p>
  <p>I then want to deploy this to a webapp
  YAML:</p>
  <pre><code>- stage: Dev
    jobs: 
    - job: DeployApp
      displayName: Deploy Web App
      pool:
        name: myPrivate
        demands: msbuild
      steps:
      - task: DownloadPipelineArtifact@2
        inputs:
          artifact: MyArtifact
      - task: AzureRmWebAppDeployment@4
        displayName: 'Deploy App'
        inputs:
          WebAppKind: 'Web App On Windows'
          azureSubscription: 'edited out...'
          WebAppName: webAppName
          package: '$(System.ArtifactsDirectory)'
          enableXmlTransform: true
  </code></pre>
  <p>Which results in this output in Azure DevOps:</p>
  <p><a href="https://i.stack.imgur.com/iFCxw.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/iFCxw.jpg" alt="enter image description here" /></a></p>
  <p>A difference in <em>chunks</em> but since size match very exactly I'm happy.</p>
  <p>I then get error on the deployment so I started look in Kudo and can see that in SitePackages all my packages are 1 kb (or empty...). I expected 61.2 MB.</p>
  <p><a href="https://i.stack.imgur.com/GwoHZ.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GwoHZ.jpg" alt="enter image description here" /></a></p>
  <p>I took my working classic deployment, and there i had this row:</p>
  <pre><code>packageForLinux:'$(System.DefaultWorkingDirectory)/_MyArtifact/MyArtifact/MyApplication.zip'
  </code></pre>
  <p>But that path wasn't even found. And packageForLinux felt wrong but doesn't matter as I understand it.</p>
  <p>So can someone please me in the right direction how to deploy a web app (on windows) using YAML?</p>