git: upgrade to 2.31.0

Cherry-picked from crrev/c/2779911

BUG=b/183757372
TEST=presubmit
RELEASE_NOTE=Upgraded dev-vcs/git to version 2.31.0. Resolves CVE-2021-21300

Change-Id: I20a0422016e268e6a974516176ef04e3aac55eb5
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/2779911
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Allen Webb <allenwebb@google.com>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/overlays/portage-stable/+/15710
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
4 files changed