Fixing broken presubmits by bumping base image version

[robscott]

What type of PR is this?
/kind bug

What this PR does / why we need it:
Presubmits are currently failing (example) with the following error:

#3 [internal] load metadata for docker.io/library/golang:1.20
#3 ERROR: failed to copy: httpReadSeeker: failed open: content at https://mirror.gcr.io/v2/library/golang/manifests/sha256:344193a70dc3588452ea39b4a1e465a8d3c91f788ae053f7ee168cebf18e0a50?ns=docker.io not found: not found
#4 [internal] load metadata for gcr.io/distroless/static:nonroot
#4 DONE 0.8s
------
 > [internal] load metadata for docker.io/library/golang:1.20:
------
Dockerfile.webhook:16
--------------------
  14 |     
  15 |     ARG BUILDPLATFORM=linux/amd64
  16 | >>> FROM --platform=$BUILDPLATFORM golang:1.20 AS build-env
  17 |     RUN mkdir -p /go/src/sig.k8s.io/gateway-api
  18 |     WORKDIR /go/src/sig.k8s.io/gateway-api
--------------------
ERROR: failed to solve: golang:1.20: failed to copy: httpReadSeeker: failed open: content at https://mirror.gcr.io/v2/library/golang/manifests/sha256:344193a70dc3588452ea39b4a1e465a8d3c91f788ae053f7ee168cebf18e0a50?ns=docker.io not found: not found
�[0;31mTest FAILED: hack/../hack/verify-examples-kind.sh 

This PR hopes to understand why that's happening and eventually fix it.

Does this PR introduce a user-facing change?:

NONE

[robscott]

Update: I thought it was going to be more complicated than this, but apparently just using a slightly different image seems to do the trick. LGTM would be appreciated to unblock other PRs.

[mikemorris]

/approve
/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mikemorris, robscott

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