lakitu: Update google-guest-agent to 20210707.00

This upgrade broke the behavior of creating and publishing SSH hostkeys
on COS, so I needed to include a patch to fix this. I will try to
upstream the patch.

BUG=b/186855818
TEST=emerge-lakitu google-guest-agent; presubmit
RELEASE_NOTE=Updated google-guest-agent to v20210707.00

Change-Id: I9f9ce2c2f996b058078cb3601c7e420ec63d101b
Reviewed-on: https://cos-review.googlesource.com/c/cos/overlays/board-overlays/+/19803
Reviewed-by: Roy Yang <royyang@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
6 files changed