Export the current data format version used by ValueSerializer.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 7e699f4595adae04745f07746f7918dba31aeb25..b215b6d6713e0f0bf9e0c811c403e5bde8d41acb 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -3145,6 +3145,11 @@ struct ValueSerializer::PrivateData {
   i::ValueSerializer serializer;
 };
 
+// static
+uint32_t ValueSerializer::GetCurrentDataFormatVersion() {
+  return i::ValueSerializer::GetCurrentDataFormatVersion();
+}
+
 ValueSerializer::ValueSerializer(Isolate* isolate)
     : ValueSerializer(isolate, nullptr) {}