set dependabot cooldown

container appraisal

test rails 7.0..8.1

cleanup versions in Appraisals

overcome frozen arrays in ActiveSupport::Dependencies for rails >= 7

require sprockets/railtie for rails >= 7

ruby >= 4 requires logger, ostruct and benchmark as gems

add/use ruby 4 in workflows

build(deps): bump actions/checkout from 5 to 6 (#16)

build(deps): bump actions/checkout from 4 to 5 (#15)

remove codeclimate badge

update check workflow badge

require logger, as it is not required by concurrent-ruby < 1.3.5

need base64, bigdecimal and mutex_m for ruby >= 3.4

github-workflows: add ruby 3.4