Remove edition of itd in more-ci The value [true] that is present in `dune-project` is the most permissive, thus keeping it is not going to create new errors. The build with [false], which is the eventual desired value, is already checked as part of the main ci, so we don't need to check it with all versions. This change will eventually simplify the migration to new workflows based on [setup-dune] so we are making this refactor as prerequisite.