Date/Time: Replace all instances of date() with gmdate().

Use of `date()` in core depends on PHP timezone set to UTC and not changed by third party code (which cannot be guaranteed).

`gmdate()` is functionally equivalent, but is not affected by PHP timezone setting: it's always UTC, which is the exact behavior the core needs.

Props nielsdeblaauw, Rarst.
Fixes #46438. See #44491.

git-svn-id: https://develop.svn.wordpress.org/trunk@45424 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/bookmark-template.php

@@ -87,7 +87,7 @@ function _walk_bookmarks( $bookmarks, $args = '' ) {
 				$title .= ' (';
 				$title .= sprintf(
 					__( 'Last updated: %s' ),
-					date(
+					gmdate(
 						get_option( 'links_updated_date_format' ),
 						$bookmark->link_updated_f + ( get_option( 'gmt_offset' ) * HOUR_IN_SECONDS )
 					)