Compatibility with LSCWP

Hi there,

Nice plugin, good job! This is the developer from https://ww.wp.xz.cn/plugins/litespeed-cache/

We got a report about the compatibility: https://github.com/litespeedtech/lscache_wp/issues/63

Can you please add the follow line to your maintenance.php line 91 in the function mt_clear_cache():

`
method_exists( ‘LiteSpeed_Cache_API’, ‘purge_all’ ) && LiteSpeed_Cache_API::purge_all() ;
`

Thanks,
Hai