Since version 3.0 all allowed IPs and subnets are exposed by the
exporter. With `-s` set on the CLI, instead of a comma-separated list,
each allowed IP and subnet will be in a single field with the schema
`allowed_ip_<index>`.
This is a simple exporter which exports the information
provided by `wg show all dump` to prometheus.
Co-authored-by: Franz Pletz <fpletz@fnordicwalking.de>