Roll SK Tool from cd1617622f0e to 15a35d1c64b9

https://skia.googlesource.com/buildbot.git/+log/cd1617622f0e..15a35d1c64b9

2021-06-03 lovisolo@google.com Update BUILD files with Gazelle.
2021-06-03 kjlubick@google.com [gold] Roll out periodic diff work
2021-06-03 49699333+dependabot[bot]@users.noreply.github.com Bump dns-packet from 1.3.1 to 1.3.4
2021-06-03 kjlubick@google.com [gold] Rename left digests to new digests in periodic tasks
2021-06-03 kjlubick@google.com [gold] Move diffwork pubsub messages from indexer to periodic service.
2021-06-03 lovisolo@google.com [bazel] Update Bazel CIPD package to v4.1.0.

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/sk-tool-skia
Please CC borenet@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/master/autoroll/README.md

Tbr: borenet@google.com
Change-Id: I4ac39fc0fefceea4b5902c1257196fa8479ae69c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/415416
Reviewed-by: skia-autoroll <skia-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: skia-autoroll <skia-autoroll@skia-public.iam.gserviceaccount.com>
1 file changed