This reverts commit db8d5d5929172f83d93865181757e154f27c24e6.

With match in readonly mode to skip fastlane credentials.

For mere experimentation.

Annoying. Clean check is a good to have but it doesn't provide an
option to exclude certain files. Namely Gemfile.lock here, that
may be modified after "bundle update" thus making the repo
erroneously look "dirty".

Room for filing a PR to fastlane.