Update deprecated icon names

assets/javascripts/discourse/templates/admin/plugins-chat.hbs

@@ -14,7 +14,7 @@
     <div class="pull-right">
       {{d-button
         action=(route-action "showSettings")
-        icon="gear"
+        icon="cog"
         title="chat_integration.settings"
         label="chat_integration.settings"}}
     </div>

assets/javascripts/discourse/templates/components/channel-details.hbs

@@ -3,7 +3,7 @@
     {{d-button
       action=editChannel
       actionParam=channel
-      icon="pencil"
+      icon="pencil-alt"
       title="chat_integration.edit_channel"
       label="chat_integration.edit_channel"}}
 
@@ -19,7 +19,7 @@
       class='cancel'
       action=(action "deleteChannel")
       actionParam=channel
-      icon="trash"
+      icon="trash-alt"
       title="chat_integration.delete_channel"
       label="chat_integration.delete_channel"}}
   </div>

assets/javascripts/discourse/templates/components/rule-row.hbs

@@ -31,14 +31,14 @@
   {{d-button
     action=edit
     actionParam=rule
-    icon="pencil"
+    icon="pencil-alt"
     class="edit"
     title="chat_integration.rule_table.edit_rule"}}
 
   {{d-button
     action=(action "delete")
     actionParam=rule
-    icon="trash-o"
+    icon="far-trash-alt"
     class="delete"
     title="chat_integration.rule_table.delete_rule"}}
 </td>