[REQ] Move cache directory

It’d be better if the cache directory were located in wp-content/cache/wp-minify. It has become more standard that cache information be stored here. If not there at least use something other than a hardcoded path to your current cache location. Like __DIR__ . '/cache/', a lot of people have their wp-content directory renamed, so your plugin really shouldn’t have it hardcoded.

If you were going to move it, I’d recommend something like WP_CONTENT_DIR . '/cache/wp-minify';

https://wordpress.org/plugins/wp-minify/