[engineeringmtm]

It can be brutal to use rubocop in an old project. Here is how we did it.

We only lint the files that changed after the date we integrated rubocop : `git -c log.showRoot=false log --no-merges --pretty=format: --name-only --since="2022-01-01"`

Then we heavily customized `.rubocop.yml` to avoid the rules that were not auto-correctable.

It was still brutal for a couple of weeks but now, maybe 2 years later, everything is fine.