Change Discord link in Footer component

Updated Discord link to point to the "introductions" channel

Author: SableRaf

src/components/Footer.js

@@ -23,7 +23,7 @@ const Footer = ({ withSidebar }) => {
             <a href={'http://github.com/processing/'} target="_blank" rel="noreferrer">GitHub</a>
           </li>
           <li>
-            <a href={'https://discord.gg/aWTgcaGdjr'} target="_blank" rel="noreferrer">Discord</a>
+            <a href={'https://discord.gg/mt2CnebPsJ'} target="_blank" rel="noreferrer">Discord</a>
           </li>
           <li>
             <a href={'https://bsky.app/profile/processing.org'} target="_blank" rel="noreferrer">Bluesky</a>