Added a -f flag to the pgp-expiry-monitor tool.
It takes the fingerprint of a PGP key and looks it up on keys.openpgp.org to get the keyfile to verify.

% pgp-expiry-monitor -f 401F1D483C69BF624364CC01E9A68DCFA3A54203 -v
Key A3A54203 (401f1d483c69bf624364cc01e9a68dcfa3a54203) expires on 2030-04-13
Key 29A48884 (1e8838bdcf9adf702496866f6baf170e29a48884) expires on 2025-10-15
Key B645E283 (47122b88b77ece545effb494498ea9eab645e283) expires on 2025-11-17
Key 93DDE912 (2f21f0dd9af127d61363423d4099876b93dde912) expires on 2027-04-24
Key 0240ACAF (a1f4c70962f89c2e628e8f05d29a32fd0240acaf) expires on 2026-04-09
Key 0B691623 (0d0bc31f58b8d18cb97c31eeebd187b60b691623) expires on 2027-04-13
Key 3AB76067 (43a83177a4ec64a62bae1ac77d779e883ab76067) expires on 2026-04-09
Key 7AE809A1 (9a6d5dbde2703d7c54806f1b5acb66c47ae809a1) expires on 2027-04-13