main/lua-filesystem: correct rock_manifest location
$_rockname was not set so the rock_manifest was installed as /usr/lib/luarocks/rocks-$lver/$_rockver/rock_manifest.
We are currently working on getting Alpine Linux 3.21 out. This means that merge requests that are not aimed to help with that (only affecting testing, new aports) have a lower priority at the moment. Please be patient, they will be eventually picked up.
$_rockname was not set so the rock_manifest was installed as /usr/lib/luarocks/rocks-$lver/$_rockver/rock_manifest.