README: Add Multus configuration NOTE (#84)

* README: Add Multus configuration NOTE

This Commit Adds a note in README regarding Multus CNI expected configuration
Specifying the requirement for Multus CNI to utilize kubernetes API in its operations
As ib-kubernetes relies on net-attach-def CR for proper configuration of infiniband network
for a Pod.

Co-authored-by: Adrian Chiris <[email protected]>

Author: DmytroLinkin

README.md

@@ -93,6 +93,10 @@ data:
   GUID_POOL_RANGE_END: "02:FF:FF:FF:FF:FF:FF:FF" # The last guid in the pool
 ```
 
+> __Note:__ For Infiniband workloads to work properly, multus CNI must be configured to work with kubernetes API
+> by specifying the `kubeconfig` field in its configurations. If it is missing, then the Pod's infiniband network
+> will not be properly set up.
+
 ## Plugins
 
 Subnet Manager Plugin to configure PKeys (Partition Keys) in the InfiniBand fabric.