Update sys-apps/shadow to v4.12.3

BUG=b/334249014
TEST=presubmit
RELEASE_NOTE=Updated sys-apps/shadow to v4.12.3. This resolves
CVE-2013-4235.

cos-patch: security-moderate
Change-Id: Ie549c9e401907b94991565e691dfee654a0bf3b9
Reviewed-on: https://cos-review.googlesource.com/c/cos/overlays/board-overlays/+/69451
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Michael Kochera <kochera@google.com>
Main-Branch-Verified: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
5 files changed