It fails with: `write() argument must be str, not bytes`.

R=sokcevic@google.com

Change-Id: If6787140ea863ce3761a5c3747eb0b857b22fa47
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3276505Reviewed-by: Josip Sokcevic <sokcevic@google.com>
Commit-Queue: Vadim Shtayura <vadimsh@chromium.org>