Merge pull request #5547 from Abbotton/patch-1

[Fix] 修复未引用Str类导致在Laravel5.5 LTS版本中报错的问题

Author: jxlwqq

src/AdminServiceProvider.php

@@ -5,6 +5,7 @@
 use Encore\Admin\Layout\Content;
 use Illuminate\Routing\Router;
 use Illuminate\Support\Arr;
+use Illuminate\Support\Str;
 use Illuminate\Support\Facades\Blade;
 use Illuminate\Support\ServiceProvider;
 
@@ -99,7 +100,7 @@ public function boot()
      */
     protected function ensureHttps()
     {
-        $is_admin = \Str::startsWith(request()->getRequestUri(), '/'.ltrim(config('admin.route.prefix'), '/'));
+        $is_admin = Str::startsWith(request()->getRequestUri(), '/'.ltrim(config('admin.route.prefix'), '/'));
         if ((config('admin.https') || config('admin.secure')) && $is_admin) {
             url()->forceScheme('https');
             $this->app['request']->server->set('HTTPS', true);