Fix GitRegistry::url ret type

Signed-off-by: Jiahao XU <30436523+NobodyXu@users.noreply.github.com>

crates/binstalk-registry/src/git_registry.rs

@@ -73,7 +73,7 @@ impl GitRegistry {
         }))
     }
 
-    pub fn url(&self) -> impl Display + '_ {
+    pub fn url(&self) -> &GitUrl {
         &self.0.url
     }