[Lvfs-announce] LVFS::DeviceFlags for no HDMI/DP update failure

Hi all,

We've recently had a bug reported to fwupd which told us that [on some
hardware], the UEFI UpdateCapsule process would fail because there is
no HDMI/DP display attached. I've added some code in
https://github.com/fwupd/fwupd/commit/a71d595759717516a197c9fde918e2686eeae148
which adds this check, but it will require firmware to "opt-in" to
this new requirement. If a firmware opts-in then the user will be
warned *before* the update is scheduled that a display must be
connected to continue -- which is a much better user experience than
failing after the user has rebooted to deploy the update.

To use this, the metainfo device flag can be populated from the
firmware metadata:

  <custom>
    <value key="LVFS::DeviceFlags">display-required</value>
  </custom>

It can also be added on the LVFS website for existing firmware using
the "Update" tab of the specific firmware "Component". The flag is
used for all versions matching the specific AppStream ID, and so only
one stable firmware needs to be modified.

If anybody has any concerns or questions, please let me know offlist. Thanks,

Richard.