Allow volumeClaimTemplate name to be not provided

[bobcatfish]

Expected Behavior

Since the tekton controller is completely managing the lifecycle of PVCs created with volumeClaimTemplate, as an author of a Run specifying it, i might not care what the name of the PVC is. I'd love it if the controller could automatically generate one for me so I can skip the whole metadata section of the template if I don't need it.

Actual Behavior

It looks like the PVC created will have a name with this format:

fmt.Sprintf("%s-%s-%s", claimName, workspaceName, pipelineRunName)

Additional Info

The feature was added in #2326

[jlpettersson]

I'd love it if the controller could automatically generate one for me so I can skip the whole metadata section of the template if I don't need it.

fmt.Sprintf("%s-%s-%s", claimName, workspaceName, pipelineRunName)

Since there always will be a workspaceName and a pipelineRunName, the PVC name will be -<claimName>-<pipelineRunName> and fail because the k8s compatible name can not start with a dash. We could omit the first dash in this case and let the PVC get the name <claimName>-<pipelineRunName> ?

e.g. if claimName is empty, use PVC name:

fmt.Sprintf("%s-%s", workspaceName, pipelineRunName)