Added required keys to .readthedocs.yaml

[tbkr]

No description provided.

[FussyDuck]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 3 committers have signed the CLA.

✅ simondsmart
❌ Tbskr
❌ danovaro
_{You have signed the CLA already but the status is still pending? Let us recheck it.}