Update darkstat to 3.0.712.
Requested by maintainer in PR 40128.

Changes since 3.0.711:
- Web: Add --no-macs option to hide mac addresses.
  Thanks Dennis!
- Web: Make tables prettier.
- Host detail view now triggers a DNS lookup.
- Manpage tweaks, also move from section 1 to section 8.
- Track and show how long ago a host was last seen.
  Suggested by: Prof A Olowofoyeku (The African Chief)
- Show pcap_stats (like number of packets dropped) in the web
  interface and also upon exit.

(obache)