add known issue about unity registration

content/docs/csidriver/release/unity.md

@@ -23,6 +23,7 @@ description: Release notes for Unity XT CSI driver
 
 | Issue | Workaround |
 |-------|------------|
+| Nodes not getting registered on Unity XT. | Creating wrapper around `hostname` command inside the node pod's driver container, that fails when `-I` flag is used. This will triggrer fallback behaviour in driver and should fix the issue. |
 | Topology-related node labels are not removed automatically.  | Currently, when the driver is uninstalled, topology-related node labels are not getting removed automatically. There is an open issue in the Kubernetes to fix this. Until the fix is released, remove the labels manually after the driver un-installation using command **kubectl label node <node_name> <label1>- <label2>- ...** Example: **kubectl label node <hostname> csi-unity.dellemc.com/array123-iscsi-** Note: there must be - at the end of each label to remove it.|
 | NFS Clone - Resize of the snapshot is not supported by Unity XT Platform, however the user should never try to resize the cloned NFS volume.| Currently, when the driver takes a clone of NFS volume, it succeeds but if the user tries to resize the NFS volumesnapshot, the driver will throw an error.|
 | Delete namespace that has PVCs and pods created with the driver. The External health monitor sidecar crashes as a result of this operation.| Deleting the namespace deletes the PVCs first and then removes the pods in the namespace. This brings a condition where pods exist without their PVCs and causes the external-health-monitor sidecar to crash. This is a known issue and has been reported at https://github.com/kubernetes-csi/external-health-monitor/issues/100|