Revert "[jjo] support Kubernetes v1.22+ apiVersions deprecations"

[dbarranco]

Reverts bitnami-labs/kube-libsonnet#61

It seems that #61 is going to cause some issues with our already existing Ingresses. I've tested some new Ingresses in a 1.19 kops-based Kubernetes cluster and found-out the following:

....
[spec.rules[0].http.paths[0].backend: Invalid value: "": cannot set both port name & port number
And the Ingress resource I'm testing is:

...
  - host: <omitted>
    http:
      paths:
      - backend:
          service:
            name: <omitted>
            port:
              name: http
              number: 8080
        path: /
        pathType: ImplementationSpecific

Checking-out the official docs, it seems they also stopped adding the port number and name:

spec:
  rules:
  - http:
      paths:
      - path: /testpath
        pathType: Prefix
        backend:
          service:
            name: test
            port:
              number: 80

Ref.

cc/ @jjo

[dbarranco]

@jjo I guess tomorrow we could do a sync about this and plan accordingly how we're going to address this issue. Happy to help on this. I'm pushing this revert PR cause I wouldn't like to affect any of our production CD pipelines (they shouldn't be based in the latest commit of the libraries, but I prefer not take that risk now that we're at the end of our day)