message: fix: use get_query to fix bad query strings
diff: @@ -217,14 +217,11 @@ impl<T: DeserializeOwned + Send + 'static> List<T> {
  /// Prefer `List::next` when possible
  pub fn get_next(client: &Client, url: &str, last_id: &str) -> Response<List<T>> {
  if url.starts_with("/v1/") {
  - // TODO: Maybe parse the URL? Perhaps `List` should always parse its `url` field.
  - let mut url = url.trim_start_matches("/v1/").to_string();
  - if url.contains('?') {
  - url.push_str(&format!("&starting_after={}", last_id));
  - } else {
  - url.push_str(&format!("?starting_after={}", last_id));
  - }
  - client.get(&url)
  + let path = url.trim_start_matches("/v1/").to_string(); // the url we get back is prefixed
  + client.get_query(
  + &path,
  + [("starting_after", last_id)].iter().cloned().collect::<HashMap<_, _>>(),
  + )
  } else {
  err(StripeError::UnsupportedVersion)
  }
  