(Cosmetic?) Exceptions in build

[lukaseder]

When running a mvn clean install on the repository, this is the last output:

Exception in thread "Thread-26" Exception in thread "Thread-46" Exception in thread "Thread-34" java.lang.NoClassDefFoundError: org/testcontainers/utility/PathUtils
        at org.testcontainers.utility.MountableFile.lambda$deleteOnExit$0(MountableFile.java:318)
        at java.base/java.lang.Thread.run(Thread.java:1589)
Caused by: java.lang.ClassNotFoundException: org.testcontainers.utility.PathUtils
        ... 2 more
java.lang.NoClassDefFoundError: org/testcontainers/utility/PathUtils
        at org.testcontainers.utility.MountableFile.lambda$deleteOnExit$0(MountableFile.java:318)
        at java.base/java.lang.Thread.run(Thread.java:1589)
Caused by: java.lang.ClassNotFoundException: org.testcontainers.utility.PathUtils
        at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50)
        at org.codehaus.plexus.classworlds.realm.ClassRealm.unsynchronizedLoadClass(ClassRealm.java:271)
        at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:247)
        at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:239)
        ... 2 more
java.lang.NoClassDefFoundError: org/testcontainers/utility/PathUtils
        at org.testcontainers.utility.MountableFile.lambda$deleteOnExit$0(MountableFile.java:318)
        at java.base/java.lang.Thread.run(Thread.java:1589)
Caused by: java.lang.ClassNotFoundException: org.testcontainers.utility.PathUtils
        ... 2 more

It appears to be irrelevant to the MCVE, but is still a distraction worth solving.