fix: deprecation message about setup now warning about v4 (#1684)

Author: evilebottnawi

lib/Server.js

@@ -505,7 +505,7 @@ class Server {
       setup: () => {
         if (typeof options.setup === 'function') {
           this.log.warn(
-            'The `setup` option is deprecated and will be removed in v3. Please update your config to use `before`'
+            'The `setup` option is deprecated and will be removed in v4. Please update your config to use `before`'
           );
 
           options.setup(app, this);