Due to the fact that the AUR has been migrated to a new server, the SSH HostKeys used to connect to the host have changed. These are the new keys fingerprints:
Ed25519: SHA256:RFzBCUItH9LZS0cKB5UE6ceAYhBD5C8GeOBip8Z11+4
ECDSA: SHA256:uTa/0PndEgPZTf76e1DFqXKJEXKsn7m9ivhLQtzGOCI
RSA: SHA256:5s5cIyReIfNNVGRFdDbe3hdYiI5OelHGpw2rOUud3Q8
The fingerprints above can also be found on the AUR home page when not logged in.
URL: https://www.archlinux.org/news/aur-migration-new-ssh-hostkeys/