It would be nice if **yields-files environment variables are resolved after the step is completed

[autumn-cpt]

**yields-files is technically a cross-cutting action for the file tracking for the step, it would be nice if the environment variables were not processed until the step completes since the mapping doesn't need to be altered until then.

This would benefit the types that yield and environment variable with the results of executing the step that may feed into the file tracking, such as GitDependent