auto create a repo github variable for the doi

```
curl -X POST -H "Accept: application/vnd.github+json" -H "Authorization: Bearer XXX" -H "X-GitHub-Api-Version: 2022-11-28" https://api.github.com/repositories/1234567890/environments/dev/variables-d '{"name":"Variable_name", "value":"Test"}'
```

where XXX is the `${{ secrets.GITHUB_TOKEN }}` I think