Develop example hub which uses explicit round_ids (not `round_id_from_variable: true`)

[annakrystalli]

Discussed in https://github.com/Infectious-Disease-Modeling-Hubs/hubValidations/discussions/6

^{Originally posted by **annakrystalli** July 1, 2023} In hubs that have round specific configurations (i.e. where `round_id_from_variable: false`), how do teams signal which round they are submitting a given file too? @LucieContamin ?

After @LucieContamin's response to the above question, I've come to realise that all our current example hubs use round_id_from_variable: true so the next example we develop should be one that uses round IDs to determine rounds.

Originally posted by @annakrystalli in https://github.com/Infectious-Disease-Modeling-Hubs/hubValidations/discussions/6#discussioncomment-6344462

[annakrystalli]

Even just starting with an example tasks.json would be a great help.