title: When to use --version option in helm upgrade
body: <p>I'm trying to understand when and how <code>--version</code> option in  <code>helm upgrade</code> works. In the <a href="https://v2.helm.sh/docs/helm/#options-43" rel="nofollow noreferrer">docs</a> it says:</p>
  <blockquote>
  <p>--version string   Specify the exact chart version to use. If this is not specified, the latest version is used</p>
  </blockquote>
  <p>Lets say I have installed my app.</p>
  <pre class="lang-bash prettyprint-override"><code>helm install my-app-rls my-app-1.0.0.tgz
  </code></pre>
  <p>Now, If I update my chart and create another package <code>my-app-1.0.1.tgz</code> I can upgrade by</p>
  <pre class="lang-bash prettyprint-override"><code>helm upgrade my-app-rls my-app-1.0.1.tgz
  </code></pre>
  <p><code>Chart.yaml</code> of <code>my-app-1.0.1.tgz</code> already contains a version. When does <code>--version</code> need to be used? What is the use case of it?</p>