Bump org.apache.kafka:kafka-clients from 3.8.0 to 4.0.0 in /examples

Bumps org.apache.kafka:kafka-clients from 3.8.0 to 4.0.0.

---
updated-dependencies:
- dependency-name: org.apache.kafka:kafka-clients
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

examples/kafka-cluster/build.gradle

@@ -10,7 +10,7 @@ dependencies {
     testCompileOnly "org.projectlombok:lombok:1.18.34"
     testAnnotationProcessor "org.projectlombok:lombok:1.18.34"
     testImplementation 'org.testcontainers:kafka'
-    testImplementation 'org.apache.kafka:kafka-clients:3.8.0'
+    testImplementation 'org.apache.kafka:kafka-clients:4.0.0'
     testImplementation 'org.assertj:assertj-core:3.26.3'
     testImplementation 'com.google.guava:guava:23.0'
     testImplementation 'ch.qos.logback:logback-classic:1.3.14'