bump atc
bump atc

Submodule src/github.com/concourse/atc cc2fa8d51..0441dcc85:
  > add migration to drop versioned_resources_check_order index
  > Revert "Revert "Create migration for new BTREE index on check_order column of version_resources table.""

concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse