Bump kafkaVersion from 3.9.0 to 4.2.0

Bumps `kafkaVersion` from 3.9.0 to 4.2.0.

Updates `org.apache.kafka:kafka-clients` from 3.9.0 to 4.2.0

Updates `org.apache.kafka:connect-api` from 3.9.0 to 4.2.0

---
updated-dependencies:
- dependency-name: org.apache.kafka:kafka-clients
  dependency-version: 4.2.0
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: org.apache.kafka:connect-api
  dependency-version: 4.2.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

build.gradle

@@ -15,7 +15,7 @@ plugins {
 }
 
 ext {
-    kafkaVersion = '3.9.1'
+    kafkaVersion = '4.2.0'
     solaceJavaAPIVersion = '10.29.1'
     isSnapshot = project.version.endsWith('-SNAPSHOT')
 }