Since 2024-10-02, `gpt-4o` is actually the same as `gpt-4o-2024-08-06`.
We previously used `gpt-4o-2024-08-06`, because it was pointing to a
much better (longer context) model. Since they're both the same now,
we'd better stick to the unpinned model and make it easier for future
users to get upgrades.
This feature went through a few iterations. At some point,
a `(local timezone/time: unknown)` suffix was part of the
`baibot_now_utc` variable (hoping it improves the model's awareness that
it doesn't know the current local time), but the suffix was ultimately removed
as unnecessary.
Fixes https://github.com/etkecc/baibot/issues/10
This also includes them in the default prompts (for newly-created agents),
so that people can get a better experience out of the box.
