Update constants does pull latest versions of attributes and countries translations from Transifex and uses them to update the internal countries and attributes files.

As translations are moving to the Weblate instance at https://translations.metabrainz.org/ the script must be updated to pull the translation files from there using the Weblate API.

The translation source files for attributes and countries reside in the MusicBrainz project as part of the server source code. As Picard only has copies of those files and Weblate does not allow to sync the same files with multiple git repositories we will continue to pull and update them by script.