title: flutter build pipeline with azure devops
body: <p>i'm trying to create a build pipeline for my flutter app using azure devops.</p>
  <p>I use the azure extension for flutter from Aloïs Deniel.
  The flutter install task passes successfully.
  The Flutter build hangs and throws the following error in an infinite loop:</p>
  <pre><code> stderr: Cloning into bare repository '/Users/runner/hostedtoolcache/Flutter/1.26.0-1.0.pre-dev/macos/flutter/.pub-cache/git/cache/app_alh_packages-384b2d81da8d887d80ab6f47deedece96035bf0c'...
      fatal: could not read Username for 'https://jointhedartsidewehavewidgets.visualstudio.com': terminal prompts disabled
      exit code: 128
      
      pub get failed (server unavailable) -- attempting retry 1 in 1 second...
  </code></pre>
  <p>My azure pipeline.yaml file is quite simple:</p>
  <pre><code>variables:
    projectDirectory: 'cleanedBloc'
  
  trigger:
  - main
  
  pool:
    vmImage: 'macos-latest'
  
  steps:
  - task: FlutterInstall@0
    inputs:
      channel: 'dev'
      version: 'latest'
  - task: FlutterBuild@0
    inputs:
      target: 'ios'
      projectDirectory: $(projectDirectory)
  </code></pre>
  <p>I am happy to receive help. Thanks in advance.</p>