Helm chart: update deprecated k8s resources no longer supported in k8s 1.22

[consideRatio]

PR summary

• PR closes Helm chart: transition apiextensions.k8s.io/v1beta1 to v1 (required for use with k8s 1.22) #419 by updating the deprecated k8s API apiextensions.k8s.io/v1beta1 to apiextensions.k8s.io/v1
  • Re-imports generated files from traefik/traefik-helm-chart
  • Manually updates a k8s manifest for the DaskCluster resource definition
• The helm chart no longer supports k8s <=1.15
  • We can remain backward compatible with extra work, but I don't consider it worth doing. As comparison, the JupyterHub Helm chart requires k8s 1.17+ atm.
• The helm chart now supports k8s >=1.22
• A very efficient test running helm lint and helm template is added before the heavyweight test to build images and install the Helm chart is ran
  

Review notes

I have been a bit cautious to put in work in this repo because I'm not sure if a PR I'd make would be reviewed -> merged given limited maintenance capacity available among dask maintainers. If it would help, I'd be very happy to take on some maintenance responsibility and issue triage/review/merge PRs related to the dask-gateway Helm chart and/or documentation in general.

I'm not sure who has rights to make decisions about these matters or can review this PR, perhaps @martindurant or @jacobtomlinson?

Thanks everyone involved for an amazing project!

[jacobtomlinson]

Thanks for your efforts here @consideRatio! I'll take a look.

I'd be very happy to take on some maintenance responsibility and issue triage/review/merge PRs related to the dask-gateway Helm chart and/or documentation in general.

I'm sure this would be much appreciated! I think we would need to get a approval from a few Dask maintainers to make this happen. I'll raise it at the weekly meeting tomorrow.

[jacobtomlinson]

This generally looks great thanks!

[consideRatio]

Thanks you for your review work @jacobtomlinson! 🎉 ❤️

[TomAugspurger]

Thanks for fixing this Erik. I'll let Jacob comment on the CI approach. I'm fine with either (and the experience from jupyterhub is very helpful.).

[jcrist]

Thanks for the excellent PRs @consideRatio! You should now have write access to this repository.

[consideRatio]

Thank you @jacobtomlinson, @TomAugspurger, @jcrist! 🎉