manifest: Update manifest for main-R81-12871.B.

Steps:
 - Use the manifest from release-R81-12871.B as base.
 - Update the revision to main-R81-12871.B for kernel,
   portage-stable, chromiumos-overlay and board-overlays.

BUG=b/175733030
TEST=repo init and sync

Change-Id: I7cf83ae8ea4e31e8891ebc1719879fe4bcf968f6
Reviewed-on: https://cos-review.googlesource.com/c/cos/manifest/+/9760
Reviewed-by: Saied Kazemi <saied@google.com>
Tested-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
1 file changed
tree: f1248be526687eb3c553b978c3c5e34612058c03
  1. LICENSE
  2. PRESUBMIT.cfg
  3. README.md
  4. external_full.xml
README.md

Manifests used to checkout COS source

Usage: repo init -u https://cos.googlesource.com/cos/manifest.git && repo sync.