GH actions timeout of repos with no recent commits

[kathsherratt]

Actions are disabled for repos that haven't seen any commits in 60 days. This applies to the repos that are the source for these model submissions, e.g. the epiforecast hospitalisation forecasts.

I think we need to add a monthly commit to each automated repo to be sure they remain "active", along the lines of the fix implemented for this repo.

[sbfnk]

In general I think this is true but if I understand correctly for the hospitalisation forecasts the code is run from the actions in this repo. The source repo doesn't have any actions.