The script is already py3 compatible.

Bug: 1289280
Recipe-Nontrivial-Roll: build
Recipe-Nontrivial-Roll: build_limited
Recipe-Nontrivial-Roll: chrome_release
Recipe-Nontrivial-Roll: infra
Change-Id: I2dfd202fcb7981e5129a777424f7f730f8f33998
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3438328Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Josip Sokcevic <sokcevic@google.com>