fix clippy issues

crates/ui/src/skeleton.rs

@@ -18,6 +18,12 @@ impl Skeleton {
     }
 }
 
+impl Default for Skeleton {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl Styled for Skeleton {
     fn style(&mut self) -> &mut gpui::StyleRefinement {
         self.base.style()