As explained in https://kubernetes.io/docs/concepts/storage/persistent-volumes/#expanding-persistent-volumes-claims in order to resize Persistent Volume Claims online, some things has to be activated at cluster level:
Are this features enabled at GKE?
You can't do that on GKE, unfortunately. ExpandPersistentVolumes and PersistentVolumeClaimResize are api-server components, and on GKE you don't have access to the master node.
Note that you can't delete and create the PVC, as the pod won't get the new size. It will keep showing the previous size if doing df -h. for example. You will need to delete the pod, and re-create it.