EXPORTERS]: elastic search recorable constructor sets ecs.version field

to 8.11.0

According to ECS guidelines this field is mandatory
https://www.elastic.co/guide/en/ecs/8.11/ecs-guidelines.html

Refs #3091

Author: ShadowMaxLeb

exporters/elasticsearch/include/opentelemetry/exporters/elasticsearch/es_log_recordable.h

@@ -42,6 +42,8 @@ class ElasticSearchRecordable final : public sdk::logs::Recordable
   void WriteValue(const opentelemetry::common::AttributeValue &value, const std::string &name);
 
 public:
+  ElasticSearchRecordable() noexcept;
+
   /**
    * Returns a JSON object contain the log information
    */

exporters/elasticsearch/src/es_log_recordable.cc

@@ -197,6 +197,11 @@ void ElasticSearchRecordable::WriteValue(const opentelemetry::common::AttributeV
   }
 }
 
+ElasticSearchRecordable::ElasticSearchRecordable() noexcept : sdk::logs::Recordable()
+{
+  json_["ecs"]["version"] = "8.11.0";
+}
+
 nlohmann::json ElasticSearchRecordable::GetJSON() noexcept
 {
   return json_;