text: Title: In Oct 2023 - drop support for k8s 1.23
  Body: This is an issue to help us remember the policy (see #2591, #2979, #3040) to allow ourselves to drop support for k8s versions as long as major cloud providers has stopped supporting them.
  
  k8s | [GKE EOL](https://endoflife.date/google-kubernetes-engine) | [EKS EOL](https://endoflife.date/amazon-eks) | [AKS EOL](https://docs.microsoft.com/en-gb/azure/aks/supported-kubernetes-versions?tabs=azure-cli#aks-kubernetes-release-calendar) | Comment
  -|-|-|-|-
  1.23 | 31 Jul 2023 | 11 Oct 2023 | Apr 2023 | We can drop support 01 Oct 2023
  1.24 | 31 Oct 2023 | 31 Jan 2024 | Jul 2023 | -
  
  As part of dropping support for k8s 1.23, we can also adjust this configuration that has a fallback for k8s 1.23 or lower.
  
  https://github.com/jupyterhub/zero-to-jupyterhub-k8s/blob/2a02c402f2a23521f9538aea9a934264da3cc959/jupyterhub/templates/scheduling/user-scheduler/configmap.yaml#L9-L23