Fix typo in error text.

Author: mikew1

src/Console/Commands/ShowPermissions.php

@@ -50,7 +50,7 @@ public function handle()
                 }
 
                 if (is_null($group)) {
-                    $this->error('Groups does not exit!');
+                    $this->error('Group does not exist!');
 
                     return;
                 }