Update dogfood TaskRuns to use generate name

[bobcatfish]

Expected Behavior

Folks releasing Tekton pipelines via https://github.com/tektoncd/pipeline/tree/master/tekton#release-pipeline should be able to run the Runs as-is.

This should apply to all of the -run.yaml TaskRuns in the tekton dir.

Actual Behavior

Folks running these TaskRuns need to make sure to clean up old Runs before/after executing, or the Runs will silently do nothing since they have already completed.

Additional Info

#685 talks about using generateName instead of a hardcoded name which is probably the way to go here!

I would have just made this change while creating the 0.5 release, however I forgot about it and kicked off the TaskRun before I remembered! I'd like whoever does this to verify it actually works before committing it.

[bobcatfish]

Bahaha my run just failed, I can actually solve this myself XD

[bobcatfish]

Nevermind, I won't do this right now after all, there's an additional complication as @zxDiscovery mentioned at #685 (comment) we have to start using kubectl create instead of kubectl apply; since the -run.yaml files also contain the PipelineResources, calling create on the yaml file as-is leads to failures creating these PipelineResources since they already exist (looking forward to maybe being able to embed PipelineResources via #544 😜 😇 )

[bobcatfish]

This isn't required now that we're using tkn and I'm proposing to remove the Runs in #1274