(2022-03-07)
Problem
I upgraded ssh and now when I try to pubkey in it demands a password. In /var/log/auth.log, I find lines to the effect of:
userauth_pubkey: key type ssh-rsa not in PubkeyAcceptedAlgorithms
Solution
The "correct" solution is to regenerate your pubkeys with the latest version of putty's key generator.
If you can't or don't want to do that, you can hack:
In /etc/ssh/sshd_config, find:
...and below it add
PubkeyAcceptedKeyTypes=+ssh-rsa
...and restart sshd.