message: Use size_t as loop variable instead of int
  Fixes a compilation warning downstream when the loop variable is compared to array->size()
diff: @@ -197,7 +197,7 @@ class NLClassifier : public core::BaseTaskApi<std::vector<core::Category>,
  metadata_array,
  const std::string& name, int default_index) {
  if (metadata_array != nullptr && metadata_array->size() == tensors.size()) {
  - for (int i = 0; i < metadata_array->size(); i++) {
  + for (size_t i = 0; i < metadata_array->size(); i++) {
  if (strcmp(name.data(), metadata_array->Get(i)->name()->c_str()) == 0) {
  return i;
  }
  