Update cert-manager - almost two years outdated

[consideRatio]

Maybe we have worked around/avoided the problems in #2051 already caused by using an old version of cert-manager. But overall, I think we should try get cert-manager updated anyhow as we are at 0.15.2, released .on Jul 1, 2020 while 1.8.0 is out now, released Apr 5, 2022.

mybinder.org-deploy/.github/workflows/cd.yml

Lines 39 to 46 in 0cf568b

	# cert-mangaer versions at https://cert-manager.io/docs/release-notes/, update
	# to latest when updating and make sure to read upgrade notes. "kubectl apply"
	# will be done on CRDs but sometimes more is needed.
	#
	# NOTE: Updates to CERT_MANAGER_VERSION should also be done in the
	# test-helm-template.yaml workflow.
	#
	CERT_MANAGER_VERSION: "v0.15.2"

Since cert-manager is installed without helm instead of as a dependency of the mybinder chart, this may actually possibly be as easy as updating the version and migrating configuration if needed. I'm not sure. Any helm chart with CRDs like cert-manager is a bit tricky to manage with helm as helm won't upgrade CRDs part of a Helm chart.

Looking at https://cert-manager.io/docs/release-notes/ and inspecting how we do things, we should be good to make a few upgrade steps at least, to 1.1 based on what I've read so far.

mybinder.org-deploy/deploy.py

Lines 248 to 253 in 3804b10

	manifest_url = f"https://github.com/jetstack/cert-manager/releases/download/{version}/cert-manager.crds.yaml"
	print(BOLD + GREEN + f"Installing cert-manager CRDs {version}" + NC, flush=True)
	subprocess.check_call(
	["kubectl", "apply", "-f", manifest_url]
	)

---

This issue relates to ingress-nginx upgrades, because cert-manager needs to be able to manipulate and handle Ingress resources. I think the right call is to merge #2214 before doing anything to cert-manager, but since cert-manager isn't critical for function short term, I suggest we finish all upgrade of ingress-nginx if possible without intermixing a cert-manager upgrade in between.

[minrk]

closed by #2242