We now strongly recommend to upgrade one version at a time and to run
the tests before and after upgrading.
Note we use a `release` branch instead of an `upgrade` branch because
we've been mentioning the `release` branch in the release notes of every
release for years.
Note that, in order to have some consistency, we're always writing
"Consul Democracy", instead of using capital letters sometimes (but not
always), like we did until now.
This rule is broken in the Spanish files in which we have had to create the
headers with html in order to make the links work correctly.
These changes were made in commit: 3126fe769
