Update cluster discovery

[dturn]

What are you trying to accomplish with this PR?
Remove the need for a hard coded GVK overide list: #699
Fix v.19 & 1.20 compatiblity

How is this accomplished?
Query the raw api to determine group/versin membership per kind

What could go wrong?
The code is wrong and everything blows up because apply to told to prune the wrong things or things that doesn't exist.

** Notes **

How to generate new fixtures:
kubectl get --raw / > test/fixtures/for_unit_tests/api_raw.txt

require 'json'
raw_response = `kubectl get --raw /`
paths = JSON.parse(raw_response)["paths"].select { |p| %r{^\/api.*\/v.*$}.match(p) }
paths.each { |p| `kubectl get --raw #{p} >  test/fixtures/for_unit_tests/apis/#{p.gsub('/','_')}.txt` }

How kubeclient does this https://github.com/abonas/kubeclient/blob/master/lib/kubeclient/common.rb#L600

[timothysmith0609]

I think it's worth considering a bit more the threadsafetiness of fetching api paths

[dturn]

Flipping this from attempts: 2 to attempts: 1 didn't speed up the tests.

[karanthukral]

The approach makes a lot of sense! 👏

[dturn]

I've squashed and rebased this PR on master.

For 🎩 :

I manually deployed the hello-cloud fixtures on v1.15.10 minikube and then removed resources to test pruning.

I did the same thing with minikube start --network-plugin=cni --cni=calico which gives you a v1.20.0 cluster.

[sjagoe]

This (potentially) requires extra permissions on the cluster in order to be able to deploy with krane. Could this requirement be documented?

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: krane-deploy
rules:
- nonResourceURLs: ["/"]
  verbs: ["get"]

[airhorns]

WOOOOO!!!!!!