Remove deprecated fields podTemplate and serviceType

[savitaashture]

Changes

Issue: #849

Removed deprecated fields podTemplate and serviceType from eventlistener spec

Submitter Checklist

These are the criteria that every PR should meet, please check them off as you
review them:

• Includes tests (if functionality changed/added)
• Includes docs (if user facing)
• Commit messages follow commit message best practices
• Release notes block has been filled in or deleted (only if no user facing changes)

See the contribution guide for more details.

Release Notes

podTemplate and serviceType from eventlistener spec has been deprecated in previous release (0.9.0) and now as part of this release (0.11.0) those fields will be removed completely
so usage of podTemplate and serviceType is something like below

apiVersion: triggers.tekton.dev/v1alpha1
kind: EventListener
metadata:
  name: github-listener-interceptor
spec:
  triggers:
    ...
  resources:
    kubernetesResource:
      serviceType: NodePort
      spec:
        template:
          metadata:
            labels:
              key: "value"
            annotations:
              key: "value"
          spec:
            serviceAccountName: tekton-triggers-github-sa
            nodeSelector:
              app: test
            tolerations:
              - key: key
                value: value
                operator: Equal
                effect: NoSchedule

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-triggers-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/reconciler/v1alpha1/eventlistener/eventlistener.go	78.9%	79.2%	0.3
test/builder/eventlistener.go	79.2%	88.4%	9.2

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-triggers-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/reconciler/v1alpha1/eventlistener/eventlistener.go	78.9%	79.2%	0.3
test/builder/eventlistener.go	79.2%	88.4%	9.2

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-triggers-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/reconciler/v1alpha1/eventlistener/eventlistener.go	78.9%	79.2%	0.3
test/builder/eventlistener.go	79.2%	88.4%	9.2

[dibyom]

Can we update the Release notes to mention that the fields have been deleted?

[dibyom]

/approve

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dibyom

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[savitaashture]

Can we update the Release notes to mention that the fields have been deleted?

Done 👍

[dibyom]

/lgtm