title: git: 'credential-manager' is not a git command
body: <p>I have a server running Ubuntu 18.04.3 LTS. I want to save my git credentials, so I don't have to enter them every time. I run the following command:</p>
  <pre><code>git config --global credential.helper store
  </code></pre>
  <p>Then I <code>git pull</code> and get:</p>
  <pre><code>user@host:~/project$ git pull
  git: 'credential-manager' is not a git command. See 'git --help'.
  usage: git credential-store [&lt;options&gt;] &lt;action&gt;
  
      --file &lt;path&gt;         fetch and store credentials in &lt;path&gt;
  
  Username for 'https://gitlab.com':
  </code></pre>
  <p>After that I'm being asked for my username and password. And then the same error is printed.</p>
  <p>I've already repeated the same process several times, unsetting the <code>credential.helper</code> option with:</p>
  <pre><code>git config --global --unset credential.helper
  </code></pre>