dev-lang/go: Update dev-lang/go to v1.20.2.

Update the bootstrap sdk as well since using the previous sdk was giving
error while emerging binutils:
https://fusion2.corp.google.com/invocations/493e8721-ce86-41ea-9d26-652112de360d/log

```
binutils-2.36.1-r9:
/mnt/host/source/chromite/licensing/ebuild_license_hook: could not
import chromite module:
/mnt/host/source/chromite/licensing/ebuild_license_hook.py: No module
named 'portage'
```

BUG=b/273847775
TEST=presubmit
RELEASE_NOTE=Updated dev-lang/go to v1.20.2. This resolves
CVE-2023-24532.

Change-Id: Ifa5d9a6cdb0431833f365e92e64e2d3da25f320c
Reviewed-on: https://cos-review.googlesource.com/c/third_party/overlays/chromiumos-overlay/+/45147
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
Reviewed-by: Oleksandr Tymoshenko <ovt@google.com>
5 files changed