update copyright in footer

Author: mojavelinux

src/partials/footer-content.hbs

@@ -12,7 +12,7 @@
     </ul>
   </div>
   <div class="footer-legal">
-    <p>Except where noted, the content on this site is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license.</p>
+    <p>Copyright © {{{year}}} Dan Allen, Sarah White, and individual Asciidoctor contributors. Except where noted, the content is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) license.</p>
     <p>The UI for this site is based on the default Antora UI and is licensed under the MPL-2.0 license. Several icons are imported from <a href="https://primer.style/octicons/" target="_blank" rel="noopener">Octicons</a> and are licensed under the MIT license.</p>
     <p>AsciiDoc is a Trademark of the Eclipse Foundation, Inc.</p>
   </div>