message: use `SetOption`
diff: @@ -142,7 +142,7 @@ void AWSEnvironmentCredentialsProvider::SetExtensionOptionValue(string key, cons
  static char *evar;
  if ((evar = std::getenv(env_var_name)) != NULL)
  - this->config.options.set_variables[key] = Value(evar);
  + this->config.SetOption(key, Value(evar));
  }
  void AWSEnvironmentCredentialsProvider::SetAll() {
  