IssueTracker

Currently, GitHub App triggers fetches source from a GCS archive.  This archive is a shallow copy of the GitHub repo, such that: 1) it doesn't include submodules, and 2) it's a copy and not a clone, so it doesn't include `.git`.

This is problematic for repos with submodules on GitHub.  This is extra problematic for *private* repos with submodules on GitHub, as it creates a further complex situation of not being able to perform a build step to fully clone the repo.

As a feature request, it'd be nice to have an user-selectable options for Cloud Build to: 1) perform a clone, instead of a copy, and 2) perform shallow vs full/recursive clones