apt/keyring: use original keyring file name

src/apt/keyring.rs

@@ -26,8 +26,12 @@ pub async fn download_trust_keyring(
         ctx.command("mkdir").arg("-p").arg(trusted_gpg_d).status()?;
     }
 
-    // Generate a filename for the keyring
-    let filename = format!("pkh-{}.gpg", series);
+    // Extract the original filename from the keyring URL
+    let filename = keyring_url
+        .split('/')
+        .next_back()
+        .unwrap_or("pkh-{}.gpg")
+        .replace("{}", series);
     let keyring_path = format!("{}/{}", trusted_gpg_d, filename);
 
     // Download the keyring directly to the final location using curl