Docs: Remove Obsolete Gradle Dependencies

Author: garyrussell

spring-kafka-docs/src/main/asciidoc/appendix.adoc

@@ -2,7 +2,9 @@
 == Override Spring Boot Dependencies
 
 When using Spring for Apache Kafka in a Spring Boot application, the Apache Kafka dependency versions are determined by Spring Boot's dependency management.
-If you wish to use a different version of `kafka-clients` or `kafka-streams`, and use the embedded kafka broker for testing, you need to override their version used by Spring Boot dependency management and add two `test` artifacts for Apache Kafka.
+If you wish to use a different version of `kafka-clients` or `kafka-streams`, and use the embedded kafka broker for testing, you need to override their version used by Spring Boot dependency management; set the `kafka.version` property.
+
+Or, to use a different Spring for Apache Kafka version with a supported Spring Boot version, set the `spring-kafka.version` property.
 
 Or, to use a different Spring for Apache Kafka version with a supported Spring Boot version, set the `spring-kafka.version` property.
 For example, {project-version} is supported by Spring Boot 2.7.x which brings in 2.8.x by default.
@@ -41,13 +43,8 @@ ext['spring-kafka.version'] = '{project-version}'
 
 dependencies {
     implementation 'org.springframework.kafka:spring-kafka'
-    implementation "org.apache.kafka:kafka-streams" // optional - only needed when using kafka-streams
-    testImplementation ('org.springframework.kafka:spring-kafka-test') {
-            // needed if downgrading to Apache Kafka 2.8.1
-            exclude group: 'org.apache.zookeeper', module: 'zookeeper'
-        }
-    testImplementation "org.apache.kafka:kafka-clients:${kafka.version}:test"
-    testImplementation "org.apache.kafka:kafka_2.13:${kafka.version}:test"
+    implementation 'org.apache.kafka:kafka-streams' // optional - only needed when using kafka-streams
+    testImplementation 'org.springframework.kafka:spring-kafka-test'
 }
 ----
 ====