Property apiVersion is not allowed in TriggerTemplate

[b1zzu]

This is my TriggerTemplate:

apiVersion: triggers.tekton.dev/v1alpha1
kind: TriggerTemplate
metadata:
  name: tekton-configuration-cd
spec:
  resourcetemplates:
    - apiVersion: tekton.dev/v1beta1
      kind: TaskRun
      metadata:
        generateName: tekton-configuration-cd-
      spec:
        taskRef:
          name: tekton-configuration-cd
        resources:
          inputs:
            - name: tekton-configuration-git
              resourceRef:
                name: tekton-configuration-git

and I double-check it with the documentation multiple times and is correct, but on vs code with the tekton extension I see this error:

Tekton Pipelines: v0.13.0