zbus 3.12.0.

• ObjectServer should dispatch calls without destination since p2p connections typically don't have destinations.
• Only enable features of nix that we use.
• Support server-side cookie auth. We already supported client-side cookie-auth. zbus won't manage the cookies for you though, that's left to the bus implementation.
• Declare ConnectionBuilder as must_use. Instead of every builder method of it individually.
• Avoid a few string allocations in handshake code.
• Don't ignore errors from SID conversion to string.
• Add missing cfg on an import. Otherwise we get a warning when building for non-unix.
• Dependencies changed:
  • Home directory determination now split into a separate crate: xdg-home.
  • Drop lazy_static.
  • Drop now unneeded dirs dep.
  • Drop nix dep for non-unix (i-e Windows).