It looks like updater-gui consumes a lot of CPU if messages are sent frequently.

expiring cache enforces re-downloading metadata
skip_unavailable -> skip_if_unavailable

skip_unavailable: skips unavailable packages
skip_if_unavailable: skips unavailable repos

remove unused import

* origin/pr/186:
  Added support for custom UKI sections, such as ucode

Pull request description:

This enables the addition of sections defined in the [Xen documentation](https://xenbits.xen.org/docs/unstable/misc/efi.html).

For anyone having used the tool before, this differs in the error and help messages, but arguments that worked for the previous version will work with this version as well without modification.

* origin/pr/187:
  vmupdate: print info what's happening in dnf5
  vmupdate: cleanup
  vmupdate: expire cache + correct option name
  vmupdate: print fetching info
  vmupdate: print info if progress reporting isn't supported
  vmupdate: do not flood stdout with messages in dnf5_api
  vmupdate: try dnf4 if dnf5 is not available
  vmupdate: support dnf5 python API