Continuous integration: sphinx-versioning is obsolete

[vuilleumierc]

We currently use sphinx-versioning to create the documentation for the different versions of pyramid_oereb as part of the CI. This package is not maintained anymore and works only with older versions of Sphinx (see e.g. this issue), so it would be nice to find an alternative.

[vuilleumierc]

Unfortunately there does not seem to be a good alternative to sphinx-versioning (see e.g. the discussion here).

Currently, we use Sphinx to build the documentation, sphinx-versioning to create a multi-version documentation, and GitHub pages for the hosting. If we wanted to keep the documentation in multiple versions, it seems we should either migrate from Sphinx (to something like MKDocs) which requires some work (the input .rst files have to be adapted) or find another hosting solution than GitHub (like Read The Docs, which is not entirely free (advertisement or subscription), plus it would probably be a good thing to keep the project entirely at the same place, that is GitHub).

So for the moment I will remove sphinx-versioning from the CI, so that we can keep Sphinx up-to-date, but it means the documentation will only be available for the master branch. Any suggestions are of course welcome

[vuilleumierc]

The URL for the documentation is now https://openoereb.github.io/pyramid_oereb/