Allow public domain via the "Unlicense" in license checks

[reactive-firewall]

Unlicense is used in CI, and is fine for our MIT Licensed project, should not invalidate the check.

[reactive-firewall]

see regression:
https://github.com/reactive-firewall/multicast/actions/runs/11287652850/job/31395847201#step:7:38