Comment 1 for bug 1991954

Chiming in to say we probably want to continue shipping obsolete keys in
canonical/landscape/model/repository/constants.py since a landscape server might be mirror past suites just as much as future suites.

Side note that apt-key is deprecated, but the key can be dumped from system keyrings
gpg --keyring /usr/share/keyrings/ubuntu-archive-keyring.gpg --export --export -a F6ECB3762474EDA9D21B7022871920D1991BC93C