Use a nicer command to tail pod logs

[puneetsarna]

While what we have also works, labels is a nicer way to select k8s objects.

nginx-loadbalancer-kubernetes $ kubectl -n nlk logs -f $(kubectl -n nlk get po -l "app=nlk" --no-headers -o custom-columns=":metadata.name")
time="2024-02-28T20:35:49Z" level=info msg="Settings::Initialize"
time="2024-02-28T20:35:49Z" level=info msg="Certificates::Initialize"
time="2024-02-28T20:35:49Z" level=info msg="Certificates::Run"
I0228 20:35:49.398213       1 shared_informer.go:273] Waiting for caches to sync for nlk-handler
I0228 20:35:49.500005       1 shared_informer.go:280] Caches are synced for nlk-handler

Proposed changes

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• [x] I have read the CONTRIBUTING document
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[puneetsarna]

@ciroque @chrisakker