Update NFS extraVolumes example in values.yaml

[wasurerarenai]

The NFS volume extraVolumes example in charts/minecraft/values.yaml is missing the "nfs" key needed to define a proper NFS typed volume. Without it, the helm chart templates render an emptyDir volume instead and complain about unknown values. Adding that key renders a working NFS volume in the pod definition.

$ helm install my-minecraft minecraft-server-charts/minecraft --set minecraftServer.eula=true,persistence.dataDir.enabled=true --set "extraVolumes[0].volumeMounts[0].name=nfs,extraVolumes[0].volumeMounts[0].mountPath=/mnt/volume,extraVolumes[0].volumeMounts[0].readOnly=true,extraVolumes[0].volumes[0].name=nfs,extraVolumes[0].volumes[0].server=nas,extraVolumes[0].volumes[0].path=/mnt/minecraft"
W0513 22:19:06.143355   31321 warnings.go:70] unknown field "spec.template.spec.volumes[3].path"
W0513 22:19:06.143378   31321 warnings.go:70] unknown field "spec.template.spec.volumes[3].server"
NAME: my-minecraft
...

apiVersion: v1
kind: Pod
...
spec:
...
  template:
...
    spec:
      volumes:
...
        - name: nfs
          emptyDir: {}

=vs=

$ helm install my-minecraft minecraft-server-charts/minecraft --set minecraftServer.eula=true,persistence.dataDir.enabled=true --set "extraVolumes[0].volumeMounts[0].name=nfs,extraVolumes[0].volumeMounts[0].mountPath=/mnt/volume,extraVolumes[0].volumeMounts[0].readOnly=true,extraVolumes[0].volumes[0].name=nfs,extraVolumes[0].volumes[0].nfs.server=nas,extraVolumes[0].volumes[0].nfs.path=/mnt/minecraft"
NAME: my-minecraft

apiVersion: v1
kind: Pod
...
spec:
...
  template:
...
    spec:
      volumes:
...
  volumes:
...
    - name: nfs
      nfs:
        server: nas
        path: /mnt/minecraft