fix: Fix compile issue in rowSerializer

Summary: As title

Differential Revision: D67232576

velox/serializers/RowSerializer.h

@@ -108,7 +108,7 @@ class RowSerializer : public IterativeVectorSerializer {
 
   void flush(OutputStream* stream) override {
     for (const auto& buffer : buffers_) {
-      stream->write(buffer->asMutable<char>(), buffer->size());
+      stream->write(buffer->template asMutable<char>(), buffer->size());
     }
     buffers_.clear();
   }