[gitsync] Only send pubsub messages when something changed
[gitsync] Only send pubsub messages when something changed

Change-Id: I9db5ad7efaf8fab4b9d01b1f1ece94c4194dd7c6
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/237446
Reviewed-by: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@google.com>
Commit-Queue: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@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