title: Azure DevOps python feed error on pip install
body: <p>Established am Azure DevOps python feed and publised a python package, but can not install it in my pipeline.</p>
  
  <p><strong>azure-pipelines.yml:</strong></p>
  
  <pre><code>- task: PipAuthenticate@1
    displayName: 'Pip Authenticate'
    inputs:
      artifactFeeds: my_feed
      onlyAddExtraIndex: true
  - script: pip install my-package==0.0.1234
  </code></pre>
  
  <p><strong>output:</strong></p>
  
  <pre><code>##[section]Starting: Pip Authenticate
  ==============================================================================
  Task         : Python pip authenticate
  Description  : Authentication task for the pip client used for installing Python distributions
  Version      : 1.156.0
  Author       : Microsoft Corporation
  Help         : https://docs.microsoft.com/azure/devops/pipelines/tasks/package/pip-authenticate
  ==============================================================================
  SYSTEMVSSCONNECTION exists true
  SYSTEMVSSCONNECTION exists true
  Successfully added auth for 1 internal feeds and 0 external endpoint.
  ##[section]Finishing: Pip Authenticate
  
  ##[section]Starting: CmdLine
  ==============================================================================
  Task         : Command line
  Description  : Run a command line script using Bash on Linux and macOS and cmd.exe on Windows
  Version      : 2.151.2
  Author       : Microsoft Corporation
  Help         : https://docs.microsoft.com/azure/devops/pipelines/tasks/utility/command-line
  ==============================================================================
  Generating script.
  Script contents:
  pip install my-package==0.0.1234
  ========================== Starting Command Output ===========================
  [command]/usr/bin/bash --noprofile --norc /home/user/.../_work/_temp/029c4dab-3726-41d8-896a-ed539e6bc712.sh
  DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
  Looking in indexes: https://pypi.org/simple, https://build:****@pkgs.dev.azure.com/.../_packaging/.../pypi/simple
  Collecting my-package==0.0.1234
    ERROR: Could not find a version that satisfies the requirement my-package==0.0.1234 (from versions: none)
  ERROR: No matching distribution found for my-package==0.0.1234
  ##[error]Bash exited with code '1'.
  ##[section]Finishing: CmdLine
  </code></pre>
  
  <p><strong>How can I fix this? Thanks in advance!</strong></p>