bump atc
bump atc

[finishes #94972102]

Submodule src/github.com/concourse/atc 93fd3b1..97c661e:
  > Merge pull request #16 from concourse/stop-paused-pipelines
  > fix janky redrawing in most browsers
  > aggregated steps no longer require names

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