OSIS-4386 use 'attr' lib for CreateProgramTreeVersionCommand
OSIS-4386 use 'attr' lib for CreateProgramTreeVersionCommand

uclouvain/OSIS-Louvain,uclouvain/OSIS-Louvain,uclouvain/osis,uclouvain/osis,uclouvain/osis,uclouvain/OSIS-Louvain,uclouvain/osis