PHP 8 compatibility

[igitur]

Hi,

I'm guessing that this plugin isn't really maintained anymore, but let me test that assumption with you first. I'm getting an error after upgrading from PHP 7.2 to PHP 8.0. The create_function() method doesn't exist in PHP 8 anymore

2023-06-06 10:07:24.612178 [NOTICE] [1207683] [165.255.73.95:3750:HTTP2-17#mysite.site-443] [STDERR] PHP Fatal error:  Uncaught Error: Call to undefined function create_function() in /home/mysite/domains/mysite.site/public_html/wp-content/plugins/nextgen-nivoslider/includes/ngg-nivoslider-main.php:14
Stack trace:
#0 /home/mysite/domains/mysite.site/public_html/wp-content/plugins/nextgen-nivoslider/ngg-nivoslider.php(34): NGG_NivoSlider->__construct()
#1 /home/mysite/domains/mysite.site/public_html/wp-settings.php(453): include_once('/home/mysite/...')
#2 /home/mysite/domains/mysite.site/public_html/wp-config.php(94): require_once('/home/mysite/...')
#3 /home/mysite/domains/mysite.site/public_html/wp-load.php(50): require_once('/home/mysite/...')
#4 /home/mysite/domains/mysite.site/public_html/wp-admin/admin.php(34): require_once('/home/mysite/...')
#5 /home/mysite/domains/mysite.site/public_html/wp-admin/plugins.php(10): require_once('/home/mysite/...')
#6 {main}
  thrown in /home/mysite/domains/mysite.site/public_html/wp-content/plugins/nextgen-nivoslider/includes/ngg-nivoslider-main.php on line 14

Do you have the capacity to upgrade this plugin? Else, do you accept PRs?

thanks