Probably because Ruby 2.7 has been removed from the upstream repo? https://github.com/circleci/circleci-images disappeared as well.
I created my own build process with docker-ruby-nightly/ruby@f682f97 after some tips from an upstream maintainer in docker-library/ruby#453 (comment) because I need alpine images which this doesn't provide. Feel free to adapt this however you wish since it works for the other variants as well.
Probably because Ruby 2.7 has been removed from the upstream repo? https://github.com/circleci/circleci-images disappeared as well.
I created my own build process with docker-ruby-nightly/ruby@f682f97 after some tips from an upstream maintainer in docker-library/ruby#453 (comment) because I need alpine images which this doesn't provide. Feel free to adapt this however you wish since it works for the other variants as well.