1. Proposed title of this feature request
Ability to automatically trigger pipelineruns on image change

2. What is the nature and description of the request?
As a user with pipelines depending on the output (images) from other pipelines some sort of subscription system between pipelines and/or images from pipelines are needed.

3. Why does the customer need this? (List the business requirements here)

We run OpenShift in a corporate network and have some in-house modifications (CA-certs, Satellite etc)  that need to be done to all images in order for them to work.
Our Ops-team deliver images to the openshift namespace based on https://registry.redhat.io/ (ex. `registry.redhat.io/ubi9`) that they modify for in-house usage.
Our Dev-team use the images from the openshift namespace as a base to build their applications.
Since the number of pipelines which use a certain image isn't constant but ever changing, using a "tn" ClusterTask in the first pipeline to create pipelineruns of all the pipelines using the output image is an impossible task.
We need some way for the Dev-teams to subscribe to changes to the images in the openshift namespace and automatically trigger their pipelines based on the event.

4. List any affected packages or components.
Unknown