[PHP-WEBMASTER] [web-php] PR #1179: Add PHP Conference Japan 2024

[cocoeyes02]

Pull Request: https://github.com/php/web-php/pull/1179
Author: cocoeyes02

I have added conference information about [PHP Conference Japan 
2024](https://phpcon.php.gr.jp/2024/) in Tokyo, Japan, on December 22. Please 
review it.