Add a custom property to a SpatieMediaLibraryFileUpload based on another text field in Repeater

Repeater::make('gallery')
    ->schema([
        SpatieMediaLibraryFileUpload::make('image')
            ->collection('gallery')
            ->customProperties(['caption' => '...'])
            ->image()
            ->required(),
        TextInput::make('caption')
            ->required(),
    ])
    ->addActionLabel('Add image'),