The Docker build image for equuleus no longer builds since the release of dotenv 3.0, which requires ruby >= 3.0, not available in the Debian buster repo. We should install the dotenv 2.8.1 gem.
#65 [60/66] RUN gem install --no-document fpm #65 15.04 ERROR: Error installing fpm: #65 15.04 The last version of dotenv (>= 0) to support your Ruby & RubyGems was 2.8.1. Try installing it with `gem install dotenv -v 2.8.1` and then running the current command again #65 15.04 dotenv requires Ruby version >= 3.0. The current ruby version is 2.5.0. #65 15.05 Successfully installed rexml-3.2.6 #65 15.05 Successfully installed stud-0.0.23 #65 ERROR: process "/bin/sh -c gem install --no-document fpm" did not complete successfully: exit code: 1