Update cleanup cron to remove taskrun instead of pipelineRun

[sm43]

pac is ran inside a taskrun now instead of pipelineRun which was
earlier. this update the cleanup cron for it.

Fixes #417

Signed-off-by: Shivam Mukhade [email protected]

Submitter Checklist

• ♽ Run make test lint before submitting a PR (ie: via pre-push github hook no need to waste CPU cycle on CI
• 📖 If you are adding a user facing feature or make a change of the behavior, please make sure to document it
• 🧪 100% coverage is not a target but most of the time we would rather have a unit test if you make a code change.
• 🎁 If that's something that is possible to do please make sure to check if we can add a e2e test.
• 🔎 If there is a flakiness in the CI tests then make sure to get the flakyness fixed before merging or if that's not possible there is a good reason to bypass it.

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