migrated to jdk 21

deployments/dockerfiles/api-service.Dockerfile

deployments/dockerfiles/hashing-service.Dockerfile

deployments/dockerfiles/ipfs-service.Dockerfile

deployments/dockerfiles/post-registration-service.Dockerfile

faircommons-services/api-service/pom.xml

...eu/fairkom/faircommons/api_service/api/PublicWorkApi.java

...a/eu/fairkom/faircommons/api_service/api/WorkFileApi.java

...ons/api_service/listener/WorkRegisteredEventListener.java

.../faircommons/api_service/listener/WorkStatusListener.java

...om/faircommons/api_service/repository/WorkRepository.java

...rkom/faircommons/api_service/service/WorkFileService.java

...aircommons/api_service/service/WorkMessageDispatcher.java

.../fairkom/faircommons/api_service/service/WorkService.java

...om/faircommons/api_service/service/WorkStatusService.java

...mmons/api_service/strategy/AbstractMessageDispatcher.java

...rcommons/api_service/strategy/MetaIpfsDoneDispatcher.java

...mons/api_service/strategy/RegistrationDoneDispatcher.java

faircommons-services/common/pom.xml

...rc/main/java/eu/fairkom/faircommons/common/Constants.java

...va/eu/fairkom/faircommons/common/IdentifierGenerator.java