Use fqdn class name of File facade

Author: jan-tricks

tests/TestCase.php

@@ -2,9 +2,9 @@
 
 namespace Whitecube\Sluggable\Tests;
 
-use File;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Foundation\Application;
+use Illuminate\Support\Facades\File;
 use Orchestra\Testbench\TestCase as Orchestra;
 
 abstract class TestCase extends Orchestra