Update to gtk4-rs 0.7.1

src/widgets/image_page.rs

 use gtk::{glib, prelude::*, subclass::prelude::*};
 
 mod imp {
-    use std::cell::RefCell;
-
-    use glib::once_cell::sync::OnceCell;
+    use std::cell::{OnceCell, RefCell};
 
     use super::*;
 

src/widgets/paginator.rs

@@ -97,13 +97,13 @@ impl PaginatorWidget {
     }
 
     #[template_callback]
-    fn on_key_pressed(&self, keyval: gdk::Key) -> glib::ControlFlow {
+    fn on_key_pressed(&self, keyval: gdk::Key) -> glib::Propagation {
         if keyval == gdk::Key::Right {
             self.try_next();
         } else if keyval == gdk::Key::Left {
             self.try_previous();
         }
-        glib::ControlFlow::Continue
+        glib::Propagation::Proceed
     }
 
     #[template_callback]