Move off DockerHub for e2e images

[mattmoor]

Expected Behavior

e2e tests "just work"

Actual Behavior

Periodically the e2e tests hit DockerHub's shiny new rate-limiting, and things fail.

Example:

        INFO[0000] Retrieving image debian:9.11
        ERRO[0001] Error while retrieving image from cache: debian:9.11 GET https://index.docker.io/v2/library/debian/manifests/9.11: TOOMANYREQUESTS: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit 
        INFO[0001] Retrieving image manifest debian:9.11   

Note: the above had mirror.gcr.io configured for both Github Actions and KinD, but it is kaniko pulling the base image, which (afaik) doesn't have mirror support (or at least isn't configuring it!).

Steps to Reproduce the Problem

This is a periodic thing, run it enough and it'll pop out.

cc @vdemeester (since we chatted in slack)

[mattmoor]

In my experience ghcr.io thus far is a pretty fantastic alternative to DockerHub that's also free.

[lbernick]

/priority important-longterm

[tekton-robot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale with a justification.
Stale issues rot after an additional 30d of inactivity and eventually close.
If this issue is safe to close now please do so with /close with a justification.
If this issue should be exempted, mark the issue as frozen with /lifecycle frozen with a justification.

/lifecycle stale

Send feedback to tektoncd/plumbing.

[tekton-robot]

Stale issues rot after 30d of inactivity.
Mark the issue as fresh with /remove-lifecycle rotten with a justification.
Rotten issues close after an additional 30d of inactivity.
If this issue is safe to close now please do so with /close with a justification.
If this issue should be exempted, mark the issue as frozen with /lifecycle frozen with a justification.

/lifecycle rotten

Send feedback to tektoncd/plumbing.

[vdemeester]

/lifecycle frozen