Warn when session template on github is out of sync with spreadsheet cached template #326
Description
When a spreadsheet is created, it caches the session template. The template might change on github subsequently. If the changes to the template involve slot or date data, it does not suffice to simply refresh the cached template info in the spreadsheet: it's necessary to make sure that the room and slot metadata in the spreadsheet is still consistent with language in the template. Therefore, when refreshing GitHub data, the tool should warn us if the cached version and the GitHub version are out-of-sync.
After review, it's possible already to update the spreadsheet cache via Event > Advanced > Get Backup from Github > Fetch event info, rooms, days, slots.