timeout Step Modifier

The amount of time to limit the step's execution to, e.g. 30m for 30 minutes.

When exceeded, the step will be interrupted, with the same semantics as aborting the build (except the build will be failed, not aborted, to distinguish between human intervention and timeouts being enforced).

The following will run the unit task and cancel it if it takes longer than 1 hour and 30 minutes:

- get: foo
- task: unit
  file: foo/unit.yml
  timeout: 1h30m