Build warnings in test step

[bocytko]

https://github.com/zalando/problem-spring-web/actions/runs/13339290378/job/37260953991

Run ./mvnw verify -B
[INFO] Scanning for projects...
Warning:
Warning: Some problems were encountered while building the effective model for org.zalando:problem-violations:jar:0.29.2-SNAPSHOT
Warning: 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-javadoc-plugin is missing. @ line 64, column 21
Warning:
Warning: Some problems were encountered while building the effective model for org.zalando:problem-spring-webflux:jar:0.29.2-SNAPSHOT
Warning: 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework.security:spring-security-config:jar -> duplicate declaration of version (?) @ line 84, column 21
Warning:
Warning: It is highly recommended to fix these problems because they threaten the stability of your build.
Warning:
Warning: For this reason, future Maven versions might no longer support building such malformed projects.