🐛 build: fix image push job by disabling CGO when building kustomize

[furkatgofurov7]

What this PR does / why we need it:
Passes CGO=enabled to building kustomize from tools folder to be able to build it within the container successfully

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #132
Related to: kubernetes-sigs/cluster-api#8784

Try it:

$docker run -it --entrypoint /bin/bash gcr.io/k8s-staging-test-infra/gcb-docker-gcloud:v20220609-2e4c91eb7e
bash-5.1# export CGO_ENABLED=0
bash-5.1# go install sigs.k8s.io/kustomize/kustomize/v5@v5.0.1
bash-5.1# which kustomize
/go/bin/kustomize

Additional notes:
Copy of kubernetes-sigs/cluster-api#6231. All credits to @sbueringer 🎉

[furkatgofurov7]

/cc @alexander-demicev @Fedosin @damdo @JoelSpeed

[alexander-demicev]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alexander-demicev

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[Fedosin]

/lgtm