refactor(Elastic Rest Client) add compatibility mode with ES8

solidify-index/src/main/java/ch/unige/solidify/index/ElasticsearchClientProvider.java

@@ -31,6 +31,7 @@ import org.apache.http.impl.client.BasicCredentialsProvider;
 import org.elasticsearch.client.RestClient;
 import org.elasticsearch.client.RestClientBuilder;
 import org.elasticsearch.client.RestHighLevelClient;
+import org.elasticsearch.client.RestHighLevelClientBuilder;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.context.annotation.Profile;
 import org.springframework.stereotype.Service;
@@ -59,12 +60,14 @@ public class ElasticsearchClientProvider {
     if (indexProperties.getConfig().isSslEnabled()) {
       scheme = "https";
     }
+
     HttpHost host = new HttpHost(indexProperties.getConfig().getHost(), indexProperties.getConfig().getPort(), scheme);
     RestClientBuilder restClientBuilder = RestClient.builder(host);
     restClientBuilder.setHttpClientConfigCallback(httpClientBuilder -> httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider));
 
-    this.elasticsearchClient = new RestHighLevelClient(restClientBuilder);
-
+    this.elasticsearchClient = new RestHighLevelClientBuilder(restClientBuilder.build())
+            .setApiCompatibilityMode(true)
+            .build();
   }
 
   public RestHighLevelClient getElasticsearchClient() {