fix: add read perms for CSINodes to cluster-autoscaler role

[mboersma]

Reason for Change:
cluster-autoscaler 1.16+ wants to get, list, and watch v1beta1.CSINode objects. Without this permission it logs errors:

I1003 16:46:17.597992       1 scale_down.go:554] 2 nodes found to be unremovable in simulation, will re-check them at 2019-10-03 16:51:17.596782704 +0000 UTC m=+2433.908749086
I1003 16:46:17.598160       1 scale_down.go:785] No candidates for scale down
I1003 16:46:18.587192       1 reflector.go:158] Listing and watching *v1beta1.CSINode from k8s.io/client-go/informers/factory.go:134
E1003 16:46:18.588987       1 reflector.go:123] k8s.io/client-go/informers/factory.go:134: Failed to list *v1beta1.CSINode: csinodes.storage.k8s.io is forbidden: User "system:serviceaccount:kube-system:cluster-autoscaler" cannot list resource "csinodes" in API group "storage.k8s.io" at the cluster scope
I1003 16:46:19.589195       1 reflector.go:158] Listing and watching *v1beta1.CSINode from k8s.io/client-go/informers/factory.go:134
E1003 16:46:19.591188       1 reflector.go:123] k8s.io/client-go/informers/factory.go:134: Failed to list *v1beta1.CSINode: csinodes.storage.k8s.io is forbidden: User "system:serviceaccount:kube-system:cluster-autoscaler" cannot list resource "csinodes" in API group "storage.k8s.io" at the cluster scope

Issue Fixed:

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Notes:
I tested that each permission (get, list, and watch) are actually required, and that this isn't an issue for Kubernetes cluster-autoscaler 1.15 and earlier.

[codecov]

Codecov Report

Merging #2096 into master will not change coverage.
The diff coverage is n/a.

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  Coverage    76.6%   76.6%           
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  Files         135     135           
  Lines       20606   20606           
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  Hits        15786   15786           
  Misses       3897    3897           
  Partials      923     923

[jackfrancis]

/lgtm

[acs-bot]

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