updated_at api attribute changes from a string to an object when a revision is made live.

[cfc7-unikent]

I add this here for reference since Trello does not really make sense for something I doubt we will fix.

When making a revision live the api representation of the updated_at field changes from a string to an object.
This caused some confusion with the programmes and global settings while we were producting a work-a-like api for programmes within Nova.

This happens when we do the yearly rollover of programmes and global settings.

Some screenshots to demo...

1. API snippet

2. I publish a change to that course

3. API snippet has changed format for updated_at field