Remove kind ClusterTask from generic template

[savitaashture]

Issue

tkn-pac generate uses generic template and it used to have kind: ClusterTask so when we push those changes Pipelinerun use to fail with error CouldNotGetTask

  Warning  Failed           25s (x2 over 25s)  PipelineRun             Pipeline article-pipelines/article-pull-request-qjpsq can't be Run; it contains Tasks that don't exist: Couldn't retrieve Task "git-clone": clustertasks.tekton.dev "git-clone" not found
  Normal   FinalizerUpdate  25s                pipelinerun-controller  Updated "article-pull-request-qjpsq" finalizers
  Warning  Error            25s                PipelineRun             Operation cannot be fulfilled on pipelineruns.tekton.dev "article-pull-request-qjpsq": the object has been modified; please apply your changes to the latest version and try again
  Warning  InternalError    25s                PipelineRun             2 errors occurred:
           * Couldn't retrieve Task "git-clone": clustertasks.tekton.dev "git-clone" not found
           * Operation cannot be fulfilled on pipelineruns.tekton.dev "article-pull-request-qjpsq": the object has been modified; please apply your changes to the latest version and try again
  Warning  InternalError  25s  PipelineRun  1 error occurred:
           * Couldn't retrieve Task "git-clone": clustertasks.tekton.dev "git-clone" not found

Changes

• Removed kind: ClusterTask from generic.yaml

Submitter Checklist

• [ ] ♽ Run make test lint before submitting a PR (ie: with pre-commit, no need to waste CPU cycle on CI
• [ ] 📖 If you are adding a user facing feature or make a change of the behavior, please verify that you have documented it
• [ ] 🧪 100% coverage is not a target but most of the time we would rather have a unit test if you make a code change.
• [ ] 🎁 If that's something that is possible to do please ensure to check if we can add a e2e test.
• [ ] 🔎 If there is a flakiness in the CI tests then don't necessary ignore it, better get the flakyness fixed before merging or if that's not possible there is a good reason to bypass it. (token rate limitation may be a good reason to skip).

[savitaashture]

/hold

[chmouel]

I think it's needed for when we ship on openshift-console since they fetch the template as is

maybe we should just strings.Replace them as we do here :

https://github.com/openshift-pipelines/pipelines-as-code/blob/main/pkg/cmd/tknpac/generate/template.go#L88-L95

unless https://github.com/openshift-pipelines/pipelines-as-code/blob/main/pkg/cmd/tknpac/generate/generate.go#L102-L103 is set to true (which gets autodetected if not specified)

[savitaashture]

Closing this because we have done that change intentionally to handle for Openshift