Correct pod watching in Taskrun controller

[vincent-pli]

Should use cache.FilteringResourceEventHandler rather than cache.ResourceEventHandlerFuncs.
The pod with incorrect owner will not go into the queue.

Changes

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[vincent-pli]

/assign @imjasonh

[afrittoli]

Thank you for this.
I started reading about informers but I think I need a bit more background to fully understand this.
One thing I noticed looking at controller logs is that I often get errors about resources that aren't supposed to be in the taskrun controller queue to begin with, so perhaps this is about fixing that?

Example:

{"level":"info","logger":"controller.taskrun-controller","caller":"taskrun/taskrun.go:94","msg":"task run \"istio-system/istio-telemetry-78f76f9d6\" in work queue no longer exists","knative.dev/controller":"taskrun-controller"}

[vincent-pli]

@afrittoli
Exactly, the issue will be fix by this PR.

[dibyom]

/lgtm

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