added library json

libraries/ArduinoJson/extras/fuzzing/msgpack_fuzzer.cpp

@@ -0,0 +1,11 @@
+#include <ArduinoJson.h>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  DynamicJsonDocument doc(4096);
+  DeserializationError error = deserializeMsgPack(doc, data, size);
+  if (!error) {
+    std::string json;
+    serializeMsgPack(doc, json);
+  }
+  return 0;
+}