message: build: initialize const vector explicitly
  Fixes build issue on Fedora
diff: @@ -144,9 +144,9 @@ private:
  }
  absl::optional<std::chrono::milliseconds> maxInterval() const override { return absl::nullopt; }
  - const std::vector<uint32_t> retriable_status_codes_;
  - const std::vector<Http::HeaderMatcherSharedPtr> retriable_headers_;
  - const std::vector<Http::HeaderMatcherSharedPtr> retriable_request_headers_;
  + const std::vector<uint32_t> retriable_status_codes_{};
  + const std::vector<Http::HeaderMatcherSharedPtr> retriable_headers_{};
  + const std::vector<Http::HeaderMatcherSharedPtr> retriable_request_headers_{};
  };
  struct NullShadowPolicy : public Router::ShadowPolicy {
  