Update to zbus 5.x

https://github.com/dbus2/zbus/releases/tag/zbus-5.0.0

Now requires `pub` on uses of `#[proxy]` if the generated types should
be `pub`.

timedate/src/lib.rs

@@ -22,7 +22,7 @@ use zbus::proxy;
 	default_service = "org.freedesktop.timedate1",
 	default_path = "/org/freedesktop/timedate1"
 )]
-trait TimeDate {
+pub trait TimeDate {
 	/// A list of time zones known on the local system as an array of names.
 	fn list_timezones(&self) -> zbus::Result<Vec<String>>;