docs: readthedocs builds are failing

The builds are failing for more than a year:
https://readthedocs.org/projects/python-zeroconf/builds/

### Log

```
Error

The required .readthedocs.yaml configuration file was not found at repository's root. Learn how to use this file in our [configuration file tutorial](https://docs.readthedocs.io/en/stable/config-file/index.html).
```



