Add auditable_type and auditable_id properties to Audit Model

[aSeriousDeveloper]

EDIT: imported Carbon, apparently I missed that last time. Sorry 😬

Hi, Another addition to the Audit docblock to help with PHPStan type hinting.

This one is to add the auditable_type and auditable_id columns used for the auditable relation so they can be selcted, plucked, etc. The reason for this is an example below:

Audit::query()->distinct()->pluck('auditable_type');

In PHPStan levels 7 and above, this gives the following error:

 ------ ----------------------------------------------------------------------------- 
  Line   Filament/AuditResource.php                                                   
 ------ ----------------------------------------------------------------------------- 
  241    Parameter #1 $column of method                                               
         Illuminate\Database\Eloquent\Builder<OwenIt\Auditing\Models\Audit>::pluck()  
         expects Illuminate\Contracts\Database\Query\Expression|model property        
         of OwenIt\Auditing\Models\Audit, string given.                               
         🪪 argument.type                                                             
         💡 Type #2 from the union: The given string should be a property of          
            OwenIt\Auditing\Models\Audit, auditable_type given.                       
 ------ -----------------------------------------------------------------------------

Adding the properties to the Audit model resolves this. From looking at the migration stub, the morphable prefix for the auditable column cannot be changed so there shouldn't be a risk of these type hinted properties being incorrect.

User Properties

I haven't made the same change for the user relation. The reason why is that the config (and migration) allows for altering the prefix of the user morph column.

laravel-auditing/config/audit.php

Lines 27 to 34 in c57fbec

	'user' => [
	'morph_prefix' => 'user',
	'guards' => [
	'web',
	'api',
	],
	'resolver' => OwenIt\Auditing\Resolvers\UserResolver::class,
	],

laravel-auditing/database/migrations/audits.stub

Lines 21 to 24 in c57fbec

	$table->bigIncrements('id');
	$table->string($morphPrefix . '_type')->nullable();
	$table->unsignedBigInteger($morphPrefix . '_id')->nullable();
	$table->string('event');

Therefore, trying to type hint them would be unreliable, as they can be changed.