Last action timestamp

[seqizz]

Enhancement description

Hi there 👋

First of all, thanks for this 😬 API looks very promising!

One thing which would be nice to have, an endpoint which returns the timestamp of last modify action.

The problem it solves

I'm trying to write a cli app, which turned out to be extra slow, since I didn't cache yet (and you know how "easy" cache invalidation is 😬). Since I'll try to use todoist from multiple sources, I have no idea if there is a new change which is introduced by the other app (e.g. phone) before each run. Having a simple timestamp, accessible via cheap api call (way cheaper from pulling everything) would make cache invalidation easier.

Alternatives

I am currently pulling all tasks (or a whole project) depending on the requirement, before each action. I can maybe add it, but there is no way to know when to update, as long as other client can add/remove stuff. An optimistic timeout for the local cache might be helpful too.