OpenSSH upgrade problem (8.0 => 8.4)

Dear all,

just upgraded one of my rp3440s (last login was sometime in 2019) and
stumbled across an issue with upgrading openssh-* to 8.4 from 8.0 (8.0p1-3).

More recent OpenSSH versions in Debian seem to depend on "libfido2-1",
which itself depends on "libcbor[...]". Now the problem is, that there
is no "libcbor0" (anymore?) in the archive for hppa, there's only a
"libcbor0.8", but that does not suffice the "libcbor[...]" dependency of
"libfido2-1". Strangely the buildinfo file of "libfido2-1" ([1]) states
it could install a "libcbor0" for hppa:

```
[...]
Installed-Build-Depends:
[...]
  libcbor-dev (= 0.5.0+dfsg-2),
  libcbor0 (= 0.5.0+dfsg-2),
[...]
```

[1]:
http://ftp.ports.debian.org/debian-ports/pool-hppa/main/libf/libfido2/libfido2_1.6.0-2_hppa.buildinfo

According to [2] "libfido2-1" depends on "libcbor0" for "alpha, hppa,
ia64, sparc64" and on "libcbor0.8" for every other arch (i.e. "not
alpha, hppa, ia64, sparc64").

[2]: https://packages.debian.org/sid/libfido2-1

I could solve the issue by installing this "libcbor0" ([3]) from 2018
from snapshots.debian.org and then upgrading the OpenSSH packages.

[3]:
http://snapshot.debian.org/archive/debian-ports/20180517T201824Z/pool-hppa/main/libc/libcbor/libcbor0_0.5.0%2Bdfsg-2_hppa.deb

For reference I have:

```
deb http://ftp.ports.debian.org/debian-ports unstable main
deb http://ftp.ports.debian.org/debian-ports unreleased main
deb http://ftp.ports.debian.org/debian-ports experimental main
```

...in my `/etc/apt/sources.list`.

Cheers,
Frank