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`.

locale1/src/lib.rs

@@ -9,7 +9,7 @@ use zbus::proxy;
 	default_service = "org.freedesktop.locale1",
 	default_path = "/org/freedesktop/locale1"
 )]
-trait locale1 {
+pub trait locale1 {
 	/// SetLocale method
 	fn set_locale(&self, locale: &[&str], interactive: bool) -> zbus::Result<()>;