main/lxc: add `libapparmor-dev` to makedepends

since the update to meson, LXD is broken if it detects that apparmor is available. It assumes that LXC will be apparmor capable, too so starting any container fails with the following error message:

lxc 20220924043344.558 ERROR    confile - ../src/lxc/confile.c:set_config_apparmor_profile:1651 - Invalid argument - Built without AppArmor support

I did not test this on a system without apparmor support but the code looks like it should since lsm_apparmor_ops_init would simply return NULL which would cause lsm_init_static to keep looking for other security modules.