Documentation Request: How to delete things?

Hi, how do we delete resources using safe-settings? I searched the repo and as far as I can find there is no guidance on how to delete repositories or teams. Removing them from the yml files seems to have no effect.

I tried adding a `deleted: true` which seems like it tried to do something because I got a warning:

```
probot_1 | [@octokit/request] "DELETE https://api.github.com/teams//repos//" is deprecated. It is scheduled to be removed on Mon, 01 Feb 2021 00:00:00 GMT. See https://developer.github.com/changes/2020-01-21-moving-the-team-api-endpoints
```

Thanks!