Bump kafka-clients from 2.3.1 to 2.8.0 in /examples

Bumps kafka-clients from 2.3.1 to 2.8.0.

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

Author: dependabot[bot]

examples/kafka-cluster/build.gradle

@@ -10,7 +10,7 @@ dependencies {
     testCompileOnly "org.projectlombok:lombok:1.18.20"
     testAnnotationProcessor "org.projectlombok:lombok:1.18.10"
     testImplementation 'org.testcontainers:kafka'
-    testImplementation 'org.apache.kafka:kafka-clients:2.3.1'
+    testImplementation 'org.apache.kafka:kafka-clients:2.8.0'
     testImplementation 'org.assertj:assertj-core:3.14.0'
     testImplementation 'com.google.guava:guava:23.0'
     testImplementation 'org.slf4j:slf4j-simple:1.7.30'