⬆️ [Upgrade 0.29] extra sign up fields module

[luciegrau]

Description of need

Upgrade https://github.com/OpenSourcePolitics/decidim-module-extra_user_fields module in 0.29 version

To do

• Upgrade the module on our fork

[Stef-Rousset]

PR => OpenSourcePolitics/decidim-module-extra_user_fields#9