PHP Errors

This looks a really interesting plugin, but it’s currently slowing down my site by several seconds. Query Monitor reports:

Only variables should be passed by reference
wp-content/plugins/svg-vector-icon-plugin/wordpress-svg-icons-plugin.php:115

Only variables should be passed by reference
wp-content/plugins/svg-vector-icon-plugin/wordpress-svg-icons-plugin.php:137

https://ww.wp.xz.cn/plugins/svg-vector-icon-plugin/