Added a testimonial from Mitchell Hashimoto (#704)

docs/integrations/github-actions.md

@@ -5,6 +5,10 @@ Your actions will be executed in clean macOS virtual machines with 4 Apple M2 co
 
 ## Testimonials from customers
 
+Mitchell Hashimoto, HashiCorp co-founder:
+
+> I've been using "Cirrus Runners" since [that tweet](https://twitter.com/mitchellh/status/1731071326201561194) and it has been fantastic. Huge speed increase, huge cost decrease, zero maintenance, exactly what I wanted.
+
 Max Lapides, Senior Mobile Engineer at [Tonal](https://www.tonal.com/):
 
 > Previously, we were using the GitHub‑hosted macOS runners and our iOS build took ~30 minutes. Now with Cirrus Runners, the iOS build only takes ~12 minutes. That’s a huge boost to our productivity, and for only $150/month per runner it is much less expensive too.

docs/theme/overrides/home.html

@@ -271,25 +271,21 @@
       <div class="mdx-users">
         <figure class="mdx-users__testimonial">
           <img
-            src="assets/images/users/seb-jachec.webp"
-            alt="Sebastian Jachec"
+            src="assets/images/users/mitchell-hashimoto.webp"
+            alt="Mitchell Hashimoto"
             loading="lazy"
             width="200"
             height="200"
           />
           <figcaption class="md-typeset">
-            <h2>Sebastian Jachec</h2>
+            <h2>Mitchell Hashimoto</h2>
             <h3>
-              Mobile Engineer at
-              <a href="https://daybridge.com/" target="_blank">Daybridge</a>
+              HashiCorp co-founder
             </h3>
             <hr/>
             <cite>
-              It&rsquo;s been plain-sailing with the
-              <a href="/integrations/github-actions">Cirrus Runners</a>&nbsp;&mdash;
-              they&rsquo;ve been great! They&rsquo;re consistently&nbsp;60+%
-              faster on&nbsp;workflows that we&nbsp;previously used Github
-              Actions&rsquo; macOS runners for.
+              I've been using "Cirrus Runners" since <a href="https://x.com/mitchellh/status/1731071326201561194" target="_blank">that tweet</a> and
+              it has been fantastic. Huge speed increase, huge cost decrease, zero maintenance, exactly what I wanted.
             </cite>
           </figcaption>
         </figure>