adding virtiofs (#1010)

Author: steve-fraser

api/services/microvm/v1alpha1/microvms.pb.go

@@ -516,7 +516,11 @@
       "properties": {
         "containerSource": {
           "type": "string",
-          "description": "Container is used to specify a source of a volume as a OCI container.\n\nTODO: add CSI"
+          "description": "Container is used to specify a source of a volume as a OCI container."
+        },
+        "virtiofsSource": {
+          "type": "string",
+          "title": "Used for the virtiofs source path"
         }
       },
       "description": "VolumeSource is the source of a volume. Based loosely on the volumes in Kubernetes Pod specs."