Update webhook in project settings for ReadTheDocs

[tony]

@emre I don't have proper permission for this.

We need to add a webhook for:

https://readthedocs.org/api/v2/webhook/kaptan/42107/

https://docs.readthedocs.io/en/latest/webhooks.html

[tony]

@emre Can you give me permission to edit the settings for the project on github? Or add the hook for readthedocs?