message: Remove overlooked use of caf::optional
diff: @@ -49,14 +49,15 @@ struct fixture {
  }
  template <class T>
  - optional<T> get(const settings& cfg, std::string_view key) {
  + std::optional<T> get(const settings& cfg, std::string_view key) {
  if (auto ptr = get_if<T>(&cfg, key))
  return *ptr;
  - return none;
  + else
  + return {};
  }
  template <class T>
  - optional<T> get(std::string_view key) {
  + std::optional<T> get(std::string_view key) {
  if (auto* xs = get_if<settings>(&x))
  return get<T>(*xs, key);
  else
  