fix: add cilium security group rules to sks example

[ylmrx]

Description

Adding the Cilium CNI basic/mandatory rules in the SKS examples

Checklist

(For exoscale contributors)

• Changelog updated (under Unreleased block)
• Acceptance tests OK (irrelevant here)
• For a new resource, datasource or new attributes: acceptance test added/updated

Testing

(it's only comments in an example)

[kobajagi]

Thanks @ylmrx, can you also add the (commented-out) cni setting to make example complete:
https://registry.terraform.io/providers/exoscale/exoscale/latest/docs/resources/sks_cluster#cni-1
Goes here:

terraform-provider-exoscale/examples/sks/main.tf

Lines 15 to 20 in 168d9e2

	resource "exoscale_sks_cluster" "my_sks_cluster" {
	zone = local.my_zone
	name = "my-sks-cluster"
	auto_upgrade = true
	exoscale_csi = true
	}

[sauterp]

LGTM, it would be good if you could try out the example before merging. Thanks!