Update to new cffi wheel.
Update to new cffi wheel.

This removes the libffi.so.6 dependency on Linux.

Bug: 1247674
Change-Id: I271bc6525ffbe8bd413e730b23365e1bc52aa16f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3299731
Reviewed-by: Dirk Pranke <6693ee08b084bb2ffa767f664c99b689395e0e4b@google.com>
Commit-Queue: Brian Ryner <388ea68edb4d8f934960c128120aee09a8f854bf@google.com>

CoherentLabs/depot_tools,CoherentLabs/depot_tools