Made use of libfuzzer

tests/fuzzers/response_message_parse.cpp

@@ -0,0 +1,11 @@
+#include "utility.hpp"
+#include <sstream>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  std::stringstream ss;
+  ss << std::string(reinterpret_cast<const char *>(data), size);
+  std::string version, status_code;
+  SimpleWeb::CaseInsensitiveMultimap header;
+  SimpleWeb::ResponseMessage::parse(ss, version, status_code, header);
+  return 0;
+}