Fix for PHP 8+

Hi @nomadjimbob

Would be possible to fix the plugin in order to work with PHP 8+ ?
There is only need to add a simple change in line

public static function indivtablepress_shortcode_atts( $default_atts ) {

Tested with PHP 8.3.12 and PHP 8.2.24 and works!

This issue was already reported by @qrusnell https://ww.wp.xz.cn/support/topic/php-8-compatibility-issue-5/

Many thanks