fwupd: Add support for the update action

Some future dock hardware needs the user to manually restart it after the update
has completed. This patch adds the update-action functionality and shows a
dialog box just like the existing detach-action one.
2 jobs for wip/hughsie/fwupd in 2 minutes and 59 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #794026
debian-stable-x86_64

00:01:22

passed #794025
fedora-x86_64

00:02:59