Support for PipeCD to delete a resource in CloudRunApp

[ucpr]

What would you like to be added:

I want to delete a resource, like the following, in CloudRunApp.

apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: SERVICE_NAME
spec:
...

In a Kubernetes application, in order to remove a resource, we need to put QuickSync.prune or PipelineSync.prune in the PipeCD application manifest.
It would be nice to have the same configuration for CloudRunApp.

Why is this needed:

Without this feature, developers need to delete Cloud Run on Google Cloud Console manually.