Bump spring-boot-starter-data-mongodb in /plugins/gradle/example-client

Bumps [spring-boot-starter-data-mongodb](https://github.com/spring-projects/spring-boot) from 2.4.4 to 2.5.2.
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](https://github.com/spring-projects/spring-boot/compare/v2.4.4...v2.5.2)

---
updated-dependencies:
- dependency-name: org.springframework.boot:spring-boot-starter-data-mongodb
  dependency-type: direct:production
  update-type: version-update:semver-minor
...
Signed-off-by: Ndependabot[bot] <support@github.com>

plugins/gradle/example-client/build.gradle

@@ -14,7 +14,7 @@ mainClassName = "io.github.kobylynskyi.order.Application"
 
 dependencies {
     implementation "org.springframework.boot:spring-boot-starter-web:2.4.4"
-    implementation "org.springframework.boot:spring-boot-starter-data-mongodb:2.4.4"
+    implementation "org.springframework.boot:spring-boot-starter-data-mongodb:2.5.2"
 
     implementation "com.graphql-java-kickstart:graphql-spring-boot-starter:11.0.0"
     implementation "com.graphql-java-kickstart:graphiql-spring-boot-starter:11.0.0"