Readonly callback ignored

[drsdre]

When the readonly flag is set, DateRange still allows user to change the range. For example using a callback $is_readonly which returns true:

$is_readonly = function ( $NovaRequest ) {
	/** @var NovaRequest $NovaRequest */
	/** @var RoundModel $Round */
	if ( $NovaRequest->resource() == 'App\Nova\Round' && $Round = $NovaRequest->findModelQuery()->first() ) {
		return ! $Round->isEditable();
	} else {
		return false;
	}
};

DateRange::make( 'Match period', [ 'match_period_start', 'match_period_end' ] )
         ->nullable()
         ->readonly( $is_readonly ),

[drsdre]

Mapping was missing between isReadOnly and :disabled in this compenent. Fixed with #9