title: List all files in Build Context and/or in WORKDIR when building container image
body: <p>I am trying to build a container image using Docker task on Azure Pipeline.
  I created a dockerfile, but it looks like a made a mistake cause I keep getting</p>
  
  <blockquote>
    <p>WARN saveError ENOENT: no such file or directory, open
    '/usr/src/app/package.json'</p>
  </blockquote>
  
  <p>I thought it would be good to list all files that exist in <strong>build context</strong> and/or <strong>WORKDIR</strong> so it
  would be easier for me to find a solution.</p>
  
  <p>Is there any appropriate dockerfile command, something like...</p>
  
  <blockquote>
    <p>dir</p>
    
    <p>ls</p>
  </blockquote>