Bump wiremock from 2.20.0 to 2.21.0

Bumps [wiremock](https://github.com/tomakehurst/wiremock) from 2.20.0 to 2.21.0.
- [Release notes](https://github.com/tomakehurst/wiremock/releases)
- [Changelog](https://github.com/tomakehurst/wiremock/blob/master/release-settings.gradle)
- [Commits](wiremock/wiremock@2.20.0...2.21.0)

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

Author: dependabot-support

kafka-connect-rest-source/build.gradle

@@ -8,7 +8,7 @@ dependencies {
     testImplementation group: 'org.junit.jupiter', name: 'junit-jupiter-api', version: '5.4.0'
     testRuntimeOnly group: 'org.junit.jupiter', name: 'junit-jupiter-engine', version: '5.4.0'
     testImplementation group: 'org.mockito', name: 'mockito-core', version: '2.27.0'
-    testImplementation group: 'com.github.tomakehurst', name: 'wiremock', version: '2.21.0'
+    testImplementation group: 'com.github.tomakehurst', name: 'wiremock', version: '2.23.2'
 
     testImplementation group: 'org.apache.kafka', name: 'connect-api', version: kafkaVersion
 }