Upgrade Spring Boot to 3.5.0

- Update Spring Boot version to 3.5.0
 - Enforce elasticsearch-java client to use the explicit version 8.18.1
      - This is because of the incompatibility between Spring Boot 3.4.x and 3.5.0 in using the elastic search java client versions 8.15.1 vs 8.18.1

Signed-off-by: Ilayaperumal Gopinathan <ilayaperumal.gopinathan@broadcom.com>

vector-stores/spring-ai-elasticsearch-store/pom.xml

@@ -53,6 +53,7 @@
 		<dependency>
 			<groupId>co.elastic.clients</groupId>
 			<artifactId>elasticsearch-java</artifactId>
+			<version>${elasticsearch-java.version}</version>
 		</dependency>
 
 		<!-- TESTING -->

vector-stores/spring-ai-elasticsearch-store/src/main/java/org/springframework/ai/vectorstore/elasticsearch/ElasticsearchVectorStore.java

@@ -24,6 +24,7 @@ import java.util.Optional;
 import java.util.stream.Collectors;
 
 import co.elastic.clients.elasticsearch.ElasticsearchClient;
+import co.elastic.clients.elasticsearch._types.mapping.DenseVectorSimilarity;
 import co.elastic.clients.elasticsearch.core.BulkRequest;
 import co.elastic.clients.elasticsearch.core.BulkResponse;
 import co.elastic.clients.elasticsearch.core.SearchResponse;
@@ -329,7 +330,8 @@ public class ElasticsearchVectorStore extends AbstractObservationVectorStore imp
 			this.elasticsearchClient.indices()
 				.create(cr -> cr.index(this.options.getIndexName())
 					.mappings(map -> map.properties(this.options.getEmbeddingFieldName(),
-							p -> p.denseVector(dv -> dv.similarity(this.options.getSimilarity().toString())
+							p -> p.denseVector(dv -> dv
+								.similarity(DenseVectorSimilarity.valueOf(this.options.getSimilarity().toString()))
 								.dims(this.options.getDimensions())))));
 		}
 		catch (IOException e) {