Bump mapstruct in /plugins/gradle/example-client (#512)

Bumps [mapstruct](https://github.com/mapstruct/mapstruct) from 1.4.1.Final to 1.4.2.Final.
- [Release notes](https://github.com/mapstruct/mapstruct/releases)
- [Commits](https://github.com/mapstruct/mapstruct/compare/1.4.1.Final...1.4.2.Final)
Signed-off-by: Ndependabot[bot] <support@github.com>
Co-authored-by: Ndependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

plugins/gradle/example-client/build.gradle

@@ -27,7 +27,7 @@ dependencies {
     implementation "org.apache.httpcomponents:httpclient:4.5.13"
     implementation "javax.validation:validation-api:2.0.1.Final"
 
-    implementation "org.mapstruct:mapstruct:1.4.1.Final"
+    implementation "org.mapstruct:mapstruct:1.4.2.Final"
     annotationProcessor "org.mapstruct:mapstruct-processor:1.4.2.Final"
 
     compileOnly "org.projectlombok:lombok:1.18.18"