Add sox and source repository

Base image, python:3.8-slim-buster, uses the Debian "Buster" distribution, which has reached its End-of-Life (EoL).
Its package repositories have been moved to an archive server.

BUG=b:432068604
TEST=CQ

Change-Id: I9351493dbadc8beb19d992165373faa9b3fbb378
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/6734719
Auto-Submit: Varun Srivastav <varunsrivastav@google.com>
Reviewed-by: Chris DeLaGarza <cdelagarza@google.com>
Commit-Queue: Varun Srivastav <varunsrivastav@google.com>
Tested-by: Varun Srivastav <varunsrivastav@google.com>
(cherry picked from commit f0cfd99d8ed25b18b3aeb9804284fc0c06c6ba0e)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/6813385
Reviewed-by: Kazuhiro Inaba <kinaba@chromium.org>
1 file changed