title: Using stages in Azure DevOps Pipeline : Unexpected value 'stages'
body: <p>I create an Azure-Pipelines file that starts as follows:</p>
  
  <pre><code>pool:
    vmImage: 'Ubuntu-16.04'
  
  trigger:
  - master
  
  variables:
    buildConfiguration: 'Release'
    buildPlatform: 'any cpu'
    version: '0.2.0'
    azureSubscription: 'Azure.Nupaya'
    azureAppType: 'Web App on Windows'
    webAppName: 'api'
  
  stages:
  
  - stage: 'Prepare'
    displayName: 'Prepare'
  
    jobs:
  
    - job: 'Setup'
      steps:
      - task: DotNetCoreInstaller@0
        displayName: 'Install'
        inputs:
          packageType: 'sdk'
          version: '2.2.105'
  </code></pre>
  
  <p>When I run it I get the error:</p>
  
  <pre><code> Unexpected value 'stages'
  </code></pre>
  
  <p>Isn't Stages supported in the Yaml File? </p>
  
  <p>I checked the <a href="https://docs.microsoft.com/en-us/azure/devops/pipelines/yaml-schema?view=azure-devops&amp;tabs=example" rel="noreferrer">Schema</a> in Microsoft Docs ...</p>
  
  <p>What am I missing? </p>