Add config for pipelinerun attestations

[sudo-bmitch]

Feature Request

We need to generate pipelinerun attestations with the same config as taskruns.

Current Behavior

Errors are generated looked for keys to attest/verify pipelineruns.

Expected Behavior

Pipelinerun attestations should use the kms for keys.

Possible Solution or Alternative

Copy taskrun config patches to match pipelinerun.

Context

https://tekton.dev/docs/chains/config/#pipelinerun-configuration