Bug: {$type}Id not working

[benallfree]

Seems there has been a regression in Type/Object/PostObject.php:140. The default resolver from graphql-php's Executor::defaultFieldResolver will search for $source->{$fieldName}, which of course does not exist.

This fixes it:

			'resolve'     => function ( Post $post, $args, $context, $info ) {
				return absint( $post->ID );
			},