Conflict repo creation fails sometimes

I suspect it's an eventual consistency issue or a rate limit problem.

I had to recreate the repos a couple of times before I had reached a complete success.

Would be nice if the script would check for errors, and retry or ask to retry.

```
Creating repository: conflict-practice-pdussard... Done.
Pushing to jessehouwing-training/conflict-practice-pdussard... Done.
Creating practice pull requests for jessehouwing-training/conflict-practice-pdussard...
Creating pull request: Updates to game manual...
http: warning: HTTP 403 Forbidden <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Creating pull request: Minor CSS fixes... Done.
Creating pull request: Update README... Done.
Inviting pdussard as a collaborator to conflict-practice-pdussard... Done.
```