CI system broken with k8s 1.25 (at least k3s 1.25)

[consideRatio]

Without changes to this repo, our CI system has started failing, where a created build pod get stuck in pending state.

I'm quite confident it is because we started using k8s 1.25. Note though that the jupyterhub/action-k3s-helm action is providing us with some bridging tech called cri-dockerd, so I thought maybe we wouldn't end up with issues related to that.

Oldest test failure: https://github.com/jupyterhub/binderhub/actions/runs/3210481910/jobs/5247954722#step:28:106
Most recent test success: https://github.com/jupyterhub/binderhub/actions/runs/2987255039/jobs/4789548250

[consideRatio]

I conclude its z2jh as a dependency, with the user scheduler, that doesn't work with k8s 1.25. So the fix is to upgrade to z2jh 2.0.0