bump atc
bump atc

[finishes #110291268]

Submodule src/github.com/concourse/atc af95638..b2bb1e5:
  > bump elm-ansi to 5.0.4

Signed-off-by: Corbin Halliwill <38cf05332854d0c00b392ad9da3fb5cec295aa83@pivotal.io>

concourse/concourse,zachgersh/concourse,cjcjameson/concourse,concourse/concourse,zachgersh/concourse,concourse/concourse,concourse/concourse,cjcjameson/concourse,zachgersh/concourse,cjcjameson/concourse,concourse/concourse