Before, providers were only built indirectly. Since proviers don't
depend on terraform to build they can be moved into their own collection
of packages. This also has the advantage that they can be reached
directly using an attribute path (Eg: terraform-providers.nixos).
Co-authored-by: Wael Nasreddine <wael.nasreddine@gmail.com>
This fixes the ./update-all script to actually fetch all the available
providers (thanks pagination). It was also improver to user a more
compact representation of the data.