Add documentation for auto-deploying
Add documentation for auto-deploying

Bug: skia:9734
Change-Id: I237d2f34cebc3d241c813c485e2f847a243e9070
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/264564
Reviewed-by: Ravi Mistry <9fa2e7438b8cb730f96b74865492597170561628@google.com>
Commit-Queue: Ravi Mistry <9fa2e7438b8cb730f96b74865492597170561628@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot