website: add a deprecation notice and a link to the new website (#4370)

website/themes/uppy/layout/layout.ejs

@@ -45,9 +45,7 @@ if (page.series) {
             <img class="TransloaditBar-logoImg" src="/images/transloadit-white-glyph.svg" width="20" height="20" alt="Transloadit">
           </a> -->
           <!-- <span>Uppy is an open source project by <a class="TransloaditBar-link" href="https://transloadit.com/" target="_blank">Transloadit</a></span> -->
-          <img width="24" height="16" src="/images/ua-flag.svg" alt="Flag of Ukraine">
-          &nbsp;
-          We stand with the brave people of Ukraine. Stop the war. Find out&nbsp;<a class="TransloaditBar-link" href="https://transloadit.com/blog/2022/02/ukraine" target="_blank" rel="noopener">how you can help.</a>
+          This website is no longer maintained, please visit <a href="//uppy.io">uppy.io</a> to get up-to-date info about Uppy.
         </div>
       </div>