Updates the requests version in .vpython3 to the latest available in
order to pick up a security fix. Also changes the requested version to
the Python 3-only one since Python 2 support was removed from requests.
Bug: chromium:1448265
Change-Id: I6eb4081735aee77f38793a00e9f17bdd32a52c58
Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/4581054
Commit-Queue: Mirko Bonadei <mbonadei@chromium.org>
Reviewed-by: Mirko Bonadei <mbonadei@chromium.org>