* Bump version to v1.13.0
* Add and use openat_verbose() where reasonable
* Revert "openat: Always annotate errors with filename"
* Add --readonly flag
* Add PassthroughFsRo as read-only variant
* Add a note about the required FD state for --fd
OBS-URL: https://build.opensuse.org/package/show/Virtualization/virtiofsd?expand=0&rev=30
