Bug#999435: APT::Default-Release "bullseye" disables bullseye-security

[Matt Corallo]

Package: apt
Version: 2.2.4

Default-Release now prefers the main archive over the security archive. This seems to be a behavior 
change from buster, presumably due to the renaming of the -security archive. eg

# apt-cache policy dnsutils
dnsutils:
  Installed: (none)
  Candidate: 1:9.16.15-1
  Version table:
     1:9.16.22-1~deb11u1 500
        500 http://security.debian.org/debian-security bullseye-security/main 
arm64 Packages
     1:9.16.15-1 990
        990 http://deb.debian.org/debian bullseye/main arm64 Packages