[skylab_tests] Update skylab tests cros img version

This CL will update cros image version for skylab tests. CROS_BOARD_LKGM
is updated according to chromeos/CHROMEOS_LKGM; CROS_BOARD_DEV,
CROS_BOARD_BETA and CROS_BOARD_STABLE are updated according to Omaha.

If this CL caused regressions, please revert and pause the autoroller at
https://luci-scheduler.appspot.com/jobs/chrome/lacros-skylab-tests-cros-img-roller
Also please file a bug to OS>LaCrOS>Partner, and CC svenzheng@chromium.org,
liaoyuke@chromium.org, yjt@google.com.

R=rubber-stamper@appspot.gserviceaccount.com

Change-Id: I65d98dc25920ee805a4b4d2e13654ccea1a64cac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3392981
Auto-Submit: skylab-test-cros-roller@chops-service-accounts.iam.gserviceaccount.com <skylab-test-cros-roller@chops-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#959781}