prometheus-wireguard-exporter: 3.1.0 -> 3.1.1

https://github.com/MindFlavor/prometheus_wireguard_exporter/releases/tag/3.1.1

This release adds a flag `-l` which takes an address where the exporter
is available. The default is `0.0.0.0` (previously, `0.0.0.0` was used
by default).

Please note that there are no dependency changes in Cargo and therefore
the cargo hash didn't change.