fix discord link

Author: dominicletz

_layouts/default.html

@@ -29,7 +29,7 @@
                 <a href="https://github.com/elixir-berlin/planning/issues/new?template=talk.yml">Apply as Speaker</a>
                 <a href="https://github.com/elixir-berlin/elixir-companies-berlin">Company Register</a>
                 <a href="https://join.slack.com/t/elixir-lang/shared_invite/zt-29w4dnkie-VkuKAAiVHSMmKakxrVA27w">Slack (&#x23;Berlin)</a>
-                <a href="https://discord.gg/UQY54bVw">Discord</a>
+                <a href="https://discord.gg/YD3r3cMtvT">Discord</a>
               </nav>
             </header>
           </div>