bump atc

[finishes #81247410]

Submodule src/github.com/concourse/atc c12c178..0f7d3ff:
  > thread resources through scheduler to factory
  > refactor radar runner to use dynamic ifrit group
  > split config db from db interface
  > push config down into database
  > Merge branch 'feature-fine-grained-locking-81247410' of https://github.com/luan/atc into luan-feature-fine-grained-locking-81247410