Roll back cpython version on Linux.
Bug: 1208146
Change-Id: If692ee3073e41acf4da2cd271559b86987813937
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2896108
Auto-Submit: Brian Ryner <bryner@google.com>
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Owners-Override: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>