Update WordPress to 5.2

wp-includes/feed-rdf.php

@@ -33,12 +33,7 @@ do_action( 'rss_tag_pre', 'rdf' );
 	<title><?php wp_title_rss(); ?></title>
 	<link><?php bloginfo_rss( 'url' ); ?></link>
 	<description><?php bloginfo_rss( 'description' ); ?></description>
-	<dc:date>
-	<?php
-		$date = get_lastpostmodified( 'GMT' );
-		echo $date ? mysql2date( 'Y-m-d\TH:i:s\Z', $date ) : date( 'Y-m-d\TH:i:s\Z' );
-	?>
-	</dc:date>
+	<dc:date><?php echo get_feed_build_date( 'Y-m-d\TH:i:s\Z' ); ?>	</dc:date>
 	<sy:updatePeriod>
 	<?php
 		/** This filter is documented in wp-includes/feed-rss2.php */