Don't build pages for branches other than master
We're currently building pages in any CI, so in theory a push to a branch that isn't master will overwrite our official documentation with that branch's documentation.
Not that much of a big deal for the main project since we rarely push non-master branches (we do sometimes though). But it is more of an issue in user branches. You can't use personal pages as a reference for a MR ("look, this is how it looks like") unless you stop pushing all other branches.
So we should probably have a filter for master only on the main pipeline and (maybe?) push a branch's pages into a subdirectory or something like that.