Tell HN: Ubuntu Pro now required for security fixes, even for supported releases

Canonical now requires an Ubuntu Pro subscription to get security updates, even for Ubuntu releases that are still supported. On an Ubuntu 22.04 system that's not subscribed to Ubuntu Pro, the output of running "sudo apt dist-upgrade" includes this:

  The following security updates require Ubuntu Pro with 'esm-apps' enabled:
    libopenexr25 libmagickcore-6.q16-6-extra libmagickwand-6.q16-6
    libmagickcore-6.q16-6 imagemagick-6-common
  Learn more about Ubuntu Pro at https://ubuntu.com/pro