Update Discord link in support.html

Author: murrant

_includes/support.html

@@ -8,7 +8,7 @@ <h3 class="section-subheading text-muted">We have a few ways to get in touch, th
             </div>
         </div>
         <div class="row text-center">
-            <a href="https://t.libren.ms/discord" target="_blank">
+            <a href="https://discord.gg/librenms" target="_blank">
                 <div class="col-md-4">
                     <span class="fa-stack fa-4x">
                         <i class="fa fa-circle fa-stack-2x text-primary"></i>