Fix SA1019 error by staticcheck due to deprecation

[khrm]

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

Changes

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Release Notes

NONE

[savitaashture]

The failures when bumped to Pipeline 0.50.x(LTS) #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

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[khrm]

/kind misc

[savitaashture]

/lgtm