This change fix a typo where `git_diff` is undefined and should be replaced by render_diff. Change-Id: I9f1322853b7abdf6abd8b0d287b4b538963e6674
This change adds a new dhall-diff job to verify generated config is idempotent. Change-Id: I96a335dc78c4fa74564b854997433e5be0b5e633