Warning: possible change in GH API may cause issues with safe-settings

On latest versions:

When a change is triggered and safe-settings runs for a repository, the first change made is for repository settings. Something like

```
DEBUG (mark): GitHub request: PATCH https://api.github.com/repos/ORG/REPO - 422
auto_init: true
visibility: "internal"
has_issues: false
has_projects: false
has_wiki: false
allow_squash_merge: true
allow_merge_commit: false
allow_rebase_merge: false
allow_auto_merge: true
delete_branch_on_merge: true
org: "REDACTED"
```

This request, however, has started to fail with the below message:

`"data":{"message":"Visibility is already internal.","documentation_url":"https://github.com/pricing"}}`

In case its relevant: this request also has the nebula header enabled `"headers":{"accept":"application/vnd.github.nebula-preview+json"`

I do not know where/how to track down possible changes to GH API that might cause this :/

cc @decyjphr