🔖 zbus 5.7.0

• ✨ Add ProcessFD/pidfd to peer ConnectionCredentials.
• ✨ Enable fd passing for the channel socket. It already does supports fd passing, so all we need
  to do is enable it.
• 📝 Document generated prop_changed and prop_invalidated methods.
• ⬆️a Require zvariant 5.5.2.
• ⬆️ Upgrade from yanked dep versions of futures-util.