Something went wrong installing decidim gem

[gillesdeloustal]

Hi
I installed several times decidim, thanks to script.
Each time, I get the error "something went wrong" installing decidim gem and each time, I install decidim gem thanks to https://github.com/Platoniq/decidim-install/blob/master/decidim-bionic.md and I restart the script which goes up to the end and let me start.

Since I had problems later on, this time, I decided to ask for help.
This time again, I installed lubuntu 18.04 on a I386 machine from scratch before to start the script.
Here is the trace when I repeated the script after having the error a 1st time :

Skipping step 0: check
Skipping step 1: prepare
Step 2: rbenv 
Installing rbenv
/home/pretdegilles/.rbenv already exists!
/home/pretdegilles/.rbenv/bin already in PATH
rbenv init already in bashrc
2.7.2 (set by /home/pretdegilles/.rbenv/version)
rbenv successfully installed
/home/pretdegilles/.rbenv/plugins/ruby-build already exists!

Only latest stable releases for each Ruby implementation are shown.
Use 'rbenv install --list-all / -L' to show all local versions.
Ruby 2.7.2 already installed
ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [i686-linux] installed successfully
It is recommended to logout and login again to activate .bashrc
Step 3: gems 
Installing generator dependencies
[sudo] Mot de passe de pretdegilles : 
Lecture des listes de paquets... Fait
Construction de l'arbre des dépendances       
Lecture des informations d'état... Fait
imagemagick est déjà la version la plus récente (8:6.9.7.4+dfsg-16ubuntu6.9).
libicu-dev est déjà la version la plus récente (60.2-3ubuntu3.1).
libpq-dev est déjà la version la plus récente (10.16-0ubuntu0.18.04.1).
nodejs est déjà la version la plus récente (8.10.0~dfsg-2ubuntu0.4).
0 mis à jour, 0 nouvellement installés, 0 à enlever et 0 non mis à jour.
Installing bundler
/home/pretdegilles/.gemrc already created
Installing bundler
Successfully installed bundler-2.1.4
1 gem installed
Gems environment installed successfully
Installing Decidim gem
ERROR:  While executing gem ... (Gem::DependencyError)
    Unresolved dependency found during sorting - activesupport (>= 4.2.0) (requested by rails-dom-testing-2.0.3)
Something went wrong! Aborting!

Full trace of installing gem can be seen here : http://www.infoadrets.info/nuage/nextcloud/index.php/s/corqDwp9LiDJ74p

Thank you for helping