Update portage to match ChromeOS

The new portage implements ChromeOS-specific features that are used in
new eclasses, so we need to update portage before we update the
eclasses.

BUG=b/257271340
TEST=presubmit
RELEASE_NOTE=None

Change-Id: If5629a07dac000d9baa0dc8ab415ea75cf7e58a1
Reviewed-on: https://cos-review.googlesource.com/c/third_party/overlays/chromiumos-overlay/+/39287
Reviewed-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
4 files changed