Test attributes: fixing wrongful lambda capture

constexpr doesn't need to be captured. failed ci/cd

tests/test_attributes.cpp

@@ -182,7 +182,7 @@ TEST_CASE("attribute test - multi threaded") {
  // put attributes with multiple threads simultaneously
  std::vector<std::future<void>> tasks;
  for (unsigned int i = 0; i < n_tasks; ++i) {
- auto task = std::async([&logger, i, n_values] {
+ auto task = std::async([&logger, i] {
  for (auto j = 0; j < n_values; ++j)
  logger.attrs().put(fmt_lib::format("log_{}_key_{}", i, j), fmt_lib::format("log_{}_value_{}", i, j));
  });