Add PHP 8.4 to the list

Author: derickr

docs/release-process.md

@@ -6,6 +6,7 @@ repository available according to the release schedule.
 The release schedule for each version is published on the
 [PHP wiki](https://wiki.php.net):
 
+- [PHP 8.4](https://wiki.php.net/todo/php84)
 - [PHP 8.3](https://wiki.php.net/todo/php83)
 - [PHP 8.2](https://wiki.php.net/todo/php82)
 - [PHP 8.1](https://wiki.php.net/todo/php81)