community/php7: security upgrade to 7.4.21
https://github.com/php/php-src/blob/PHP-7.4.21/NEWS#L12-L13
There's no build of pdo_firebird so skipping https://github.com/php/php-src/blob/PHP-7.4.21/NEWS#L12-L13
Edited by Andy Postnikov
https://github.com/php/php-src/blob/PHP-7.4.21/NEWS#L12-L13
There's no build of pdo_firebird so skipping https://github.com/php/php-src/blob/PHP-7.4.21/NEWS#L12-L13