E:Sub-process /usr/bin/dpkg returned an error code (1)

[Clifford Burns]

Setting up spamassassin (3.4.1-7) ...
Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.30), passed through in regex; marked by <-- HERE in m/^(.{ <-- HERE ,200}).*$/ at /usr/share/perl5/Mail/SpamAssassin/PerMsgStatus.pm line 923.
gpg: WARNING: unsafe ownership on homedir '/var/lib/spamassassin/sa-update-keys'
gpg: starting migration from earlier GnuPG versions
gpg: failed to create temporary file '/var/lib/spamassassin/sa-update-keys/.#lk0x00005602c1752930.mail-server.3479': Permission denied
gpg: can't allocate lock for '/var/lib/spamassassin/sa-update-keys/.gpg-v21-migrated': Permission denied
gpg: process '/usr/bin/gpg --homedir='/var/lib/spamassassin/sa-update-keys' --batch --no-tty --status-fd=1 -q --logger-fd=1 --import' finished: exit 2
dpkg: error processing package spamassassin (--configure):
 subprocess installed post-installation script returned error exit status 2
dpkg: dependency problems prevent configuration of sa-compile:
 sa-compile depends on spamassassin; however:
  Package spamassassin is not configured yet.

dpkg: error processing package sa-compile (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 spamassassin
 sa-compile

Upgrade complete

[Christian Ehrhardt  (paelzer)]

Hi this is a duplicate of bug 1726879 which was recently fixed in upcoming Bionic.
There are considerations there to SRU to former releases as well.
Marking this as a dup.