configuration about retention-cron - On the fly

[xdxxxdx]

Hello, it is very good to have a retention-cron set, to make the retention schedule a variable.
I am wondering how to set this key to https://github.com/Informatievlaanderen/VSDS-LDESServer4J/blob/main/docker-compose/config.local.env?
Also, is it possible/a good idea to have this key set/changed on the fly? e.g. the client wanna change it after a period..

Thanks
Xueying