Error 500 linting .gitlab-ci.yml: TypeError: no implicit conversion of Symbol into Integer

https://sentry.gitlab.net/gitlab/gitlabcom/issues/1148641/

TypeError: no implicit conversion of Symbol into Integer
  gitlab/ci/config/entry/artifacts.rb:57:in `expose_as_present?'
    !@config[:expose_as].nil?
  delegate.rb:83:in `method_missing'
    target.__send__(m, *args, &block)
  active_support/callbacks.rb:426:in `block in make_lambda'
    target.send(method, *arguments, &block)
  active_support/callbacks.rb:178:in `block (2 levels) in halting_and_conditional'
    if !halted && user_conditions.all? { |c| c.call(target, value) }
  active_support/callbacks.rb:178:in `all?'
    if !halted && user_conditions.all? { |c| c.call(target, value) }
...
(171 additional frame(s) were not displayed)

TypeError: no implicit conversion of Symbol into Integer