Update footer.html to include CoC

Code of Conduct link in the footer for the pyopensci.org website in response to issue pyOpenSci#396

Author: ayhanxian

_includes/footer.html

@@ -26,6 +26,8 @@
     <p>pyOpenSci is a fiscally sponsored project of <a href="https://communityinitiatives.org/" target="_blank">Community Initiatives</a>, a registered 501(c)3 non-profit organization based in California, USA.
       pyOpenSci is grateful for support from the <a href="https://sloan.org/" target="_blank">Sloan Foundation</a> and the <a href="https://chanzuckerberg.com/" target="_blank">Chan Zuckerberg Initiative</a>.
     </p>
+    <p>pyOpensci is dedicated to creating a welcoming, supportive and diverse community around the open source Python tools that drive open science. Our <a href="https://www.pyopensci.org/handbook/CODE_OF_CONDUCT.html" target="_blank">Code of Conduct</a> defines expected behavior and guidelines that help create such a community.
+    </p>
 
     &copy; {{ site.time | date: '%Y' }} {{ site.name | default: site.title }}</div>
   <script src="https://code.jquery.com/jquery-3.6.1.min.js" integrity="sha256-o88AwQnZB+VDvE9tvIXrMQaPlFFSUTR+nldQm1LuPXQ=" crossorigin="anonymous"></script>