Fix SA1019 error by staticcheck due to deprecation

[khrm]

Fix SA1019 error given by staticcheck due to deprecation of Pipeline v1beta1.

Changes

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• [ ] Has Docs if any changes are user facing, including updates to minimum requirements e.g. Kubernetes version bumps
• [x] Has Tests included if any functionality added or changed
• [x] Follows the commit message standard
• [x] Meets the Tekton contributor standards (including functionality, content, code)
• [x] Has a kind label. You can add one by adding a comment on this PR that contains /kind <type>. Valid types are bug, cleanup, design, documentation, feature, flake, misc, question, tep
• [ ] Release notes block below has been updated with any user facing changes (API changes, bug fixes, changes requiring upgrade notices or deprecation warnings). See some examples of good release notes.
• [ ] Release notes contains the string "action required" if the change requires additional action from users switching to the new release

Release Notes

NONE

[savitaashture]

The failures when bumped to Pipeline 0.50.x(LTS) https://github.com/tektoncd/triggers/pull/1625

pkg/apis/triggers/v1alpha1/trigger_template_validation_test.go:211:41: SA1019: pipelinev1beta1.PipelineRun is deprecated: Please use v1.PipelineRun instead. (staticcheck)
                    RawExtension: test.RawExtension(t, pipelinev1beta1.PipelineRun{

[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/resources/create.go	81.2%	68.8%	-12.5

[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
test/resources.go	42.9%	46.7%	3.8

[khrm]

/assign @dibyom

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dibyom, savitaashture

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/tektoncd/triggers/blob/main/OWNERS)~~ [dibyom,savitaashture] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[savitaashture]

/lgtm