Remove /admin/modules/update

As most updates are controlled by DPL, this page doesn't really add
value. Make it inaccessible.

Ref DDFHER-94

web/modules/custom/dpl_webmaster/src/Routing/RouteSubscriber.php

@@ -21,6 +21,14 @@ protected function alterRoutes(RouteCollection $collection): void {
     if ($route = $collection->get('update.module_install')) {
       $route->setRequirement('_access', 'FALSE');
     }
+
+    // Remove /admin/modules/update. It won't work for the majority of the
+    // listed modules (webmasters can't update contrib modules provided by DPL
+    // anyway). Limiting it to webmaster uploaded, Drupal contrib modules would
+    // be a nicer alternative, but currently out of scope.
+    if ($route = $collection->get('update.module_update')) {
+      $route->setRequirement('_access', 'FALSE');
+    }
   }
 
 }