Post merge job failing beause of invalid go version

[lentzi90]

/kind bug

What steps did you take and what happened:

We have a post merge job that builds staging images. It has been failing for some time it seems: https://prow.k8s.io/job-history/gs/kubernetes-ci-logs/logs/post-cluster-api-provider-openstack-push-images
(If you see some green builds it is most likely from backports. It is failing constantly on main.)

Error:

make -C hack/tools bin/kustomize
make[4]: Entering directory '/workspace/hack/tools'
mkdir -p bin
CGO_ENABLED=0 go build -tags=tools -o bin/kustomize sigs.k8s.io/kustomize/kustomize/v5
go: errors parsing go.mod:
/workspace/hack/tools/go.mod:3: invalid go version '1.22.7': must match format 1.23
/workspace/hack/tools/go.mod:5: unknown directive: toolchain 

What did you expect to happen:

The job should be successful (or we should remove it if we do not need it).

Anything else you would like to add:

The job is defined here: https://github.com/kubernetes/test-infra/blob/master/config/jobs/image-pushing/k8s-staging-cluster-api.yaml