Conflicts with cors plugin

[leangl]

When used in conjuction of the cors plugin, it returns the cors headers from the cached version instead of the currrent request. I have no idea how caddy plugins work, but I imagine this plugin should take effect first and hand off the cached value to the cors plugin so it can update the headers accordingly.

[leangl]

Probably related to https://github.com/nicolasazrak/caddy-cache/issues/49