Form: Adding user-defined pivot data to belongsToMany relationship

    public static function form(Form $form): Form
    {
        return $form
            ->schema([
                CheckboxList::make('allowedTargets')
                    ->disabledOn('edit')
                    ->relationship(name: 'allowedTargets', titleAttribute: 'name')
                    ->pivotData([
                        TextInput::make('allowed_file_extensions')
                            ->label('Allowed File Extensions')
                            ->required(),
                    ])              
            ]);
    }