Gemfile

source 'https://rubygems.org'

# something broke in the CDDL 0.12.1 update (github actions fails to install a native dependency somehow), 
# a fix was published by cddl for 0.12.4 so we need at least that (see https://github.com/martinthomson/i-d-template/issues/433#issuecomment-2173153568)
gem 'cddl', '~> 0.12.4'