migrate to localStorageCapacityIsolation kubelet option from feature gate

[BenTheElder]

The LocalStorageCapacityIsolation feature will be GA in v1.25.0 and thus there will be no feature gate, but for rootless users like this I've requested a kubelet config option that will be available in v1.25.0 thanks to @jinxu97. You can set localStorageCapacityIsolation: false in the kubelet config instead of disabling the feature gate when Kubernetes v1.25.0 is out.

I've identified this project as using the feature gate, so this issue is a friendly heads up about the coming removal and replacement 😅

see: kubernetes/kubernetes#111513, kubernetes/enhancements#361, coming in Kubernetes v1.25.0

[TristanCacqueray]

@BenTheElder Thank you for the heads up, that's really appreciated :)