Add shutdown to fwupd

We added a plug to “shutdown” in

This is required because after installing an UEFI capsule, fwupd needs to reboot the machine.

Could you please allow fwupd to connect to shutdown?

+1 from me for auto-connect shutdown to fwupd since as explained its required to reboot the system after installing an UEFI capsule. Can other @reviewers please vote?

+1 from me too - this is entirely consistent with the expected operation of this snap.

+2 votes for, 0 against. Granting auto-connect of shutdown to fwupd. This is now live.