feat: 1.13.12, support external command

src/cmd_external_public_key.rs

@@ -98,5 +98,9 @@ fn fetch_public_key(parameter: &str, serial_opt: &Option<&str>) -> XResult<Vec<u
                 simple_error!("Invalid algorithm: {}", key.algorithm.to_str())
             }
         }
+        KeyUri::ExternalCommandKey(key) => {
+            let parameter = cmd_hmac_decrypt::try_decrypt(&mut None, &key.parameter)?;
+            external_command_rs::external_public_key(&key.external_command, &parameter)
+        }
     }
 }