Allow nested lists in config.yml. `steps` List
Often I repetition inside the jobs-steps-List. By leveraging YAML alias and references one could have a macro like functionality in config.yml:
- run: doit -f dodo-new.py submodules
- restore_cache: …
- run: doit -f dodo-new.py BUILD
- save_cache: …
- run: doit -f dodo-new.py CICHECK CITEST
Using YAML `<<:` merge as suggested in https://circleci.com/blog/circleci-hacks-reuse-yaml-in-your-circleci-config-with-yaml/ does not work with steps because steps is a list. Do the config shown above dos not work currently.
But if Circle CI would accept a list of lists (basically run `steps.flatten()`) it would enable using this functionality reducing config duplication without much added complexity.
https://discuss.circleci.com/t/yaml-anchors-implementation-incomplete/16916 is the same problem.