Redmine 4.2.3 - Rspec error

[ephysthos]

Dear support,
I'm trying to deploy the last git version of the plugin, but if i migrate it, i got this error message :

rake aborted! NameError: uninitialized constant RSpec /home/redmine/redmine-4.2.3/plugins/redmine_git_hosting/lib/tasks/ci_tools.rake:6:in block (2 levels) in <top (required)>'
/home/redmine/redmine-4.2.3/plugins/redmine_git_hosting/lib/tasks/ci_tools.rake:4:in block in <top (required)>' /home/redmine/redmine-4.2.3/plugins/redmine_git_hosting/lib/tasks/ci_tools.rake:3:in <top (required)>'
/home/redmine/redmine-4.2.3/lib/tasks/redmine.rake:202:in block in <top (required)>' /home/redmine/redmine-4.2.3/lib/tasks/redmine.rake:202:in each'
/home/redmine/redmine-4.2.3/lib/tasks/redmine.rake:202:in <top (required)>' /home/redmine/.rvm/gems/ruby-2.6.6/gems/railties-5.2.6/lib/rails/engine.rb:656:in block in run_tasks_blocks'
/home/redmine/.rvm/gems/ruby-2.6.6/gems/railties-5.2.6/lib/rails/engine.rb:656:in each' /home/redmine/.rvm/gems/ruby-2.6.6/gems/railties-5.2.6/lib/rails/engine.rb:656:in run_tasks_blocks'
/home/redmine/.rvm/gems/ruby-2.6.6/gems/railties-5.2.6/lib/rails/application.rb:515:in run_tasks_blocks' /home/redmine/.rvm/gems/ruby-2.6.6/gems/railties-5.2.6/lib/rails/engine.rb:459:in load_tasks'
/home/redmine/.rvm/gems/ruby-2.6.6/gems/railties-5.2.6/lib/rails/railtie.rb:190:in public_send' /home/redmine/.rvm/gems/ruby-2.6.6/gems/railties-5.2.6/lib/rails/railtie.rb:190:in method_missing'
/home/redmine/redmine-4.2.3/Rakefile:7:in <top (required)>' /home/redmine/.rvm/gems/ruby-2.6.6/gems/rake-13.0.6/exe/rake:27:in <top (required)>'
/home/redmine/.rvm/gems/ruby-2.6.6/bin/ruby_executable_hooks:22:in eval' /home/redmine/.rvm/gems/ruby-2.6.6/bin/ruby_executable_hooks:22:in

'
(See full trace by running task with --trace)`

Do you have a solution in order to install it ?
Many thanks,
Guillaume.