bump atc
bump atc

Submodule src/github.com/concourse/atc 2889764..1ccdd85:
  > remove dead stripes code
  > Revert "add slight shadow to job text"

concourse/concourse,longnguyen11288/concourse,beni55/concourse,zachgersh/concourse,longnguyen11288/concourse,jbayer/concourse,beni55/concourse,squeedee/concourse,jbayer/concourse,sedouard/concourse,holgero/concourse,zachgersh/concourse,cjcjameson/concourse,Amit-PivotalLabs/concourse,Amit-PivotalLabs/concourse,jbayer/concourse,Amit-PivotalLabs/concourse,longnguyen11288/concourse,squeedee/concourse,concourse/concourse,CloudCredo/concourse,concourse/concourse,holgero/concourse,holgero/concourse,cjcjameson/concourse,CloudCredo/concourse,sedouard/concourse,squeedee/concourse,zachgersh/concourse,CloudCredo/concourse,concourse/concourse,beni55/concourse,cjcjameson/concourse,sedouard/concourse,concourse/concourse