Revert "Revert "Update toolbox base debian image to buster.""

This reverts commit 2b6752db331b2f63867a1b32b18d92e8f08c9641.

Reason for revert: Chiron disk size was increased, so this change should no longer fail tests.

Change-Id: Ia4357ebd2053b88c631c9fcd52a8e606f9710607
Reviewed-on: https://cos-review.googlesource.com/c/cos/overlays/board-overlays/+/8880
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Saied Kazemi <saied@google.com>
1 file changed