Replace deprecated function DataSource::resolve_post_object

src/class-config.php

@@ -799,7 +799,7 @@ protected function register_graphql_field( string $type_name, string $field_name
 					'resolve' => function( $root, $args, $context, $info ) use ( $acf_field ) {
 						$value = $this->get_acf_field_value( $root, $acf_field );
 
-						return DataSource::resolve_post_object( (int) $value, $context );
+						return $context->get_loader( 'post' )->load_deferred( (int) $value );
 					},
 				];
 				break;