Easily access installed version information

[ncskier]

Expected Behavior

After installing Tekton Pipelines, I expect there to be an easy way to find the version of Tekton Pipelines that I am running.

Actual Behavior

As far as I know, there is not an easy way to find what version of Tekton Pipelines I have running.

Steps to Reproduce the Problem

1. Install a version of Tekton Pipelines
2. Try to verify what version of Tekton Pipelines you are running

Additional Info

According to these Istio guidelines, deployments should have an app and version label. Adding a version label to the Tekton Pipelines deployments would make it easy to verify what version of Tekton Pipelines is running.

The version label: This label indicates the version of the application corresponding to the particular deployment.

[vdemeester]

/kind feature

We "kinda" have this in #1758 but I do like the idea of using something that is broadly used in the k8s community 👼

[vdemeester]

/assign