title: az: 'upgrade' is not in the 'az' command group
body: <p>I want to upgrade azure cli to 2.26.1 version from 2.0.81 in window subsystem of linux(wsl ubuntu). I am trying to use command <code>az upgrade</code> . It is giving following error:</p>
  <blockquote>
  <p>az: 'upgrade' is not in the 'az' command group. See 'az --help'. If the command is from an extension, please make sure the corresponding extension is installed. To learn more about extensions, please visit <a href="https://docs.microsoft.com/en-us/cli/azure/azure-cli-extensions-overview" rel="nofollow noreferrer">https://docs.microsoft.com/en-us/cli/azure/azure-cli-extensions-overview</a></p>
  </blockquote>
  <p>Is there some way to upgrade it in ubuntu?</p>