Support .yaml extension for our configuration file

[humitos]

Currently we only support .yml extension, which make some users (including myself) to be confused.

Probably, we need to just modifiy this file (https://github.com/rtfd/readthedocs-build/blob/bf2d1267c9a3dfa0b94588f23549ec527d5d5532/readthedocs_build/config/config.py#L17) to add the new names with the .yaml extension.

(take into account that .yaml is the official extension of the YAML file: http://yaml.org/faq.html)

We need:

• modify that file pointed here
• update the docs to reflect the new file names
• test this manually
• write some unit tests

Related: #4100

[stsewd]

Maybe a Good First Issue?

[StefanoChiodino]

This seems easy enough for me to get me started...hopefully ;)

[StefanoChiodino]

Looking into this I've found mention of environment.yml, mkdocs.yml. No mention of yaml extension for those so either they have the same problem or they are not correctly documented. Would those be look at in another issue?

[agjohnson]

Also, the python YAML implementation will parse JSON as well, perhaps we extend this even further :)

[StefanoChiodino]

Just realised: is .readthedocs.yaml also valid?

[agjohnson]

@StefanoChiodino yup, that is valid, some folks liked the idea of keeping the file hidden