Bump elasticsearch-rest-client in /modules/elasticsearch

Bumps [elasticsearch-rest-client](https://github.com/elastic/elasticsearch) from 7.14.1 to 7.15.0.
- [Release notes](https://github.com/elastic/elasticsearch/releases)
- [Commits](elastic/elasticsearch@v7.14.1...v7.15.0)

---
updated-dependencies:
- 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]>

modules/elasticsearch/build.gradle

@@ -2,7 +2,7 @@ description = "TestContainers :: elasticsearch"
 
 dependencies {
     api project(':testcontainers')
-    testImplementation "org.elasticsearch.client:elasticsearch-rest-client:7.14.1"
+    testImplementation "org.elasticsearch.client:elasticsearch-rest-client:7.15.0"
     testImplementation "org.elasticsearch.client:transport:7.15.0"
     testImplementation 'org.rnorth.visible-assertions:visible-assertions:2.1.2'
 }