Bug#990069: openssh-server: Not accepting new connections during Debian 10 -> 11 upgrade

[Olaf van der Spek]

So I think it's not accepting new connections from the start of the
upgrade run until the end:
Setting up openssh-sftp-server (1:8.4p1-5) ...
Setting up console-setup (1.203) ...
Setting up mime-support (3.66) ...
Setting up openssh-server (1:8.4p1-5) ...
Installing new version of config file /etc/init.d/ssh ...
Installing new version of config file /etc/ssh/moduli ...
Replacing config file /etc/ssh/sshd_config with new version
rescue-ssh.target is a disabled or a static unit, not starting it.