Update documentation to specify the new Gerrit style CQ keywords

BUG=skia:6667

NOTRY=true
DOCS_PREVIEW= https://skia.org/?cl=17762
Change-Id: I440b5565589102ae6026b5da4716fd43d4a48d6a
Reviewed-on: https://skia-review.googlesource.com/17762
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Ravi Mistry <rmistry@google.com>
2 files changed