This is an issue brought on by HP, not Apple. They requested the certificate for some of their signed printer software be revoked, causing that message to appear.
See here: https://tidbits.com/2020/10/26/code-signing-snafu-breaks-many-hp-printers/
The Register understands from sources familiar with the matter
that HP Inc asked Apple to revoke its printer driver code-signing
certificates. It appears this request backfired as it left users unable
to print. A HP Inc spokesperson told us on Friday night:
"We unintentionally revoked credentials on some older versions of Mac
drivers. This caused a temporary disruption for those customers and we
are working with Apple to restore the drivers. In the meantime, we
recommend users experiencing this problem to uninstall the HP driver and
use the native AirPrint driver to print to their printer."
I believe its been resolved, downloading the new drivers from HPs site should now resolve the problem.