miss makezero in slice init

[alingse]

I was running github actions to run linter makezero for top github golang repos.

see issues alingse/go-linter-runner#1

and the github actions output https://github.com/alingse/go-linter-runner/actions/runs/9242985516/job/25426520521

====================================================================================================
append to slice `oldIPsStrings` with non-zero initialized length at https://github.com/rancher/rke/blob/release/v1.5/pki/util.go#L512:1[9](https://github.com/alingse/go-linter-runner/actions/runs/9242985516/job/25426520521#step:4:10)
append to slice `newIPsStrings` with non-zero initialized length at https://github.com/rancher/rke/blob/release/v1.5/pki/util.go#L513:19
append to slice `Env` with non-zero initialized length at https://github.com/rancher/rke/blob/release/v1.5/cluster/plan.go#L216:9
append to slice `Env` with non-zero initialized length at https://github.com/rancher/rke/blob/release/v1.5/cluster/plan.go#L298:9
append to slice `Env` with non-zero initialized length at https://github.com/rancher/rke/blob/release/v1.5/cluster/plan.go#L306:9
append to slice `Env` with non-zero initialized length at https://github.com/rancher/rke/blob/release/v1.5/cluster/plan.go#L339:8
====================================================================================================

the oldIPsStrings := make([]string, len(oldIPs)) should be oldIPsStrings := make([]string, 0, len(oldIPs))

[github-actions]

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