Bump elasticsearch.version from 8.7.0 to 8.8.1

Bumps `elasticsearch.version` from 8.7.0 to 8.8.1.

Updates `elasticsearch-java` from 8.7.0 to 8.8.1
- [Release notes](https://github.com/elastic/elasticsearch-java/releases)
- [Changelog](https://github.com/elastic/elasticsearch-java/blob/main/CHANGELOG.md)
- [Commits](elastic/elasticsearch-java@v8.7.0...v8.8.1)

Updates `elasticsearch-rest-client` from 8.7.0 to 8.8.1
- [Release notes](https://github.com/elastic/elasticsearch/releases)
- [Changelog](https://github.com/elastic/elasticsearch/blob/main/CHANGELOG.md)
- [Commits](elastic/elasticsearch@v8.7.0...v8.8.1)

---
updated-dependencies:
- dependency-name: co.elastic.clients:elasticsearch-java
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.elasticsearch.client:elasticsearch-rest-client
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

pom.xml

@@ -24,7 +24,7 @@
         <java.compiler.version>17</java.compiler.version>
 
         <spring.version>6.0.9</spring.version>
-        <elasticsearch.version>8.7.0</elasticsearch.version>
+        <elasticsearch.version>8.8.1</elasticsearch.version>
         <beyonder.version>8.6-SNAPSHOT</beyonder.version>
         <slf4j.version>2.0.7</slf4j.version>
         <log4j.version>2.20.0</log4j.version>