Helm chart: Quote wireguard psk to fix config errors

[koskev]

Description

When using the helm chart with a wireguard psk, the value is not quoted inside net-conf.json.
This results in the SubnetManager config parse to fail.

Steps to reproduce

kubectl create ns kube-flannel
kubectl label --overwrite ns kube-flannel pod-security.kubernetes.io/enforce=privileged
helm repo add flannel https://flannel-io.github.io/flannel/
helm repo update
helm install flannel --set podCidr="10.244.0.0/16" --set flannel.backend="wireguard" --set flannel.psk="SQrrIYA1R4A/zlTkJXP3WWE3Sk+20YJ7w946IGQto/o=" --namespace kube-flannel flannel/flannel

kubectl -n kube-flannel logs pods/kube-flannel-ds-l28qk

[..]
Failed to create SubnetManager: error parsing subnet config: invalid character 'S' after object key:value pair

The resulting config is

[..]
  net-conf.json: |
    {
      "Network": "10.244.0.0/16",
      "Backend": {
        "PSK": SQrrIYA1R4A/zlTkJXP3WWE3Sk+20YJ7w946IGQto/o=,
        "Type": "wireguard"
      }
    }

Quoting the value fixes this issue.

Release Note

None required