Fixed admin_route() twig function to work properly with Grav 1.7.0-rc.4, which fixes Route base

CHANGELOG.md

@@ -13,6 +13,7 @@
     * Fixed saving data with empty field, default value (from config, plugin, theme) was used instead
     * Fixed JS bug is using empty Grav URI param key
     * Fixed bug in toggleable field being disabled with empty value (`''` `0`, `false`, `[]`...)
+    * Fixed `admin_route()` twig function to work properly with Grav 1.7.0-rc.4, which fixes `Route` base
 
 # v1.10.0-rc.3
 ## 01/02/2020

classes/plugin/Admin.php

@@ -314,13 +314,15 @@ class Admin
         $languageCode = $languageCode ?? $language->getActive();
         $languagePrefix = $languageCode ? '/' . $languageCode : '';
 
+        $root = $this->grav['uri']->rootUrl();
+
         $parts = [
             'path' => $path,
             'query' => '',
             'query_params' => [],
             'grav' => [
                 // TODO: Make URL to be /admin/en, not /en/admin.
-                'root' => preg_replace('`//+`', '/', RouteFactory::getRoot() . $languagePrefix . $this->base),
+                'root' => preg_replace('`//+`', '/', $root . $languagePrefix . $this->base),
                 'language' => '', //$languageCode,
                 'route' => ltrim($path, '/'),
                 'params' => ''