Add missing rustbot to the log repository

[Urgau]

The log repo has had a triagebot.toml for quite some time now, but never gave the permissions to rustbot/triagebot.

This is starting to cause some issues for triagebot as we have been trying to update some review comments for a few days. Let's fix the inconsistency by giving rustbot the permissions.

[Mark-Simulacrum]

Hm, this seems fine, but I'd expect us to not try to run handlers if we don't have permissions to do so (or else we need this in every/all repositories, right?)

[Urgau]

I'd expect us to not try to run handlers if we don't have permissions to do so (or else we need this in every/all repositories, right?)

We current don't do any check permission check, we (maybe naïvely) trust that if a repo has a triagebot.toml that it has the right permissions.

We do have some exceptions for org-wide features, but it's manual and rely on the same principal (assume rights if triagebot.toml file present).