Build RTD for each commit in `develop`

[LecrisUT]

I wanted to reference some things that are coming in 4.0, but there is no online build of the documentation to do so. Please enable the build for all commits on develop branch. There are relevant options to make latest build only on tags and the branch build to be de-prioritized.

[qiaojunfeng]

The current latest build points to the develop branch, probably you can already use that as references?
(e.g. https://wannier90.readthedocs.io/en/latest/user_guide/wannier90/parameters/ contains the last merged PR #559)

[LecrisUT]

Oh, my bad, that is indeed the case. I was looking at the top-right section where it was indicating that it points to the tag v3.1.0. Could that part be fixed?

[qiaojunfeng]

Oh that is a feature of mkdocs-material theme, showing the newest github tag.
We can disable it, but will lose other niceties such as pointer to the github repo URL, stars, and forks.

Probably with the 4.0 release, readthedocs can build at least two versions: v4.0 and lastest, and it should default to v4.0, then the ambiguity should disapear? (Currently there is only one version latest, because at v3.1.0 we were not using mkdocs, so RTD can only built latest and default to that).

[LecrisUT]

Oh that is a feature of mkdocs-material theme, showing the newest github tag.

Isn't it configurable to specify if it should show the current branch or the latest version (or both)? Seems like a reasonable feature request for mkdocs-material.