client: update isolated client
client: update isolated client

https://chromium.googlesource.com/infra/infra/+log/3a488b0a91d683d7538f8829d46f6e721e74f2a6..9713d76a9f8196d0b8a062262f7910e5244cfe4d/DEPS

    2020-06-03 nodir@chromium.org [resultdb] Regenerate protobufs
    2020-06-03 71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org downloader: use fixed permission for files
    2020-06-03 jsca@google.com [milo] Regen proto files after protobuf upgrade.

Bug: 1069704
Change-Id: I8ce6145ac6078869c6cfddaab35179f19f482d96
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/2228921
Commit-Queue: Ye Kuang <1cd89f22f3967fc3dcb883b53940be4b98ec483f@google.com>
Reviewed-by: Ye Kuang <1cd89f22f3967fc3dcb883b53940be4b98ec483f@google.com>
Auto-Submit: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>

luci/luci-py,luci/luci-py,luci/luci-py,luci/luci-py