Update readme

Author: sohelamin

README.md

@@ -2,7 +2,7 @@
 An admin panel for managing users, roles, permissions & crud.
 
 ### Requirements
-    Laravel >=6.0
+    Laravel >=5.5
     PHP >= 7.0
 
 ## Features

src/LaravelAdminCommand.php

@@ -57,7 +57,7 @@ public function handle()
         $this->call('vendor:publish', ['--provider' => 'Spatie\Activitylog\ActivitylogServiceProvider', '--tag' => 'migrations']);
 
         $this->info("Dumping the composer autoload");
-        (new Process('composer dump-autoload'))->run();
+        (new Process(['composer dump-autoload']))->run();
 
         $this->info("Migrating the database tables into your application");
         $this->call('migrate');