Add more detail on configuring jobs.

Docs-Preview: https://skia.org/?cl=56020
Change-Id: I7d28d7921ab9c650498f4f8a06533f7e5df19a36
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/56020
Auto-Submit: Ben Wagner <benjaminwagner@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
2 files changed