Add UDPA oneof annotation

Signed-off-by: Lidi Zheng <lidiz@google.com>

api/envoy/service/status/v3/csds.proto

@@ -84,19 +84,20 @@ message ClientStatusRequest {
 }
 
 // Detailed config (per xDS) with status.
-// [#next-free-field: 7]
+// [#next-free-field: 8]
 message PerXdsConfig {
   option (udpa.annotations.versioning).previous_message_type =
       "envoy.service.status.v2.PerXdsConfig";
 
   // Config status generated by management servers. Will not be present if the
   // CSDS server is an xDS client.
-  ConfigStatus status = 1;
+  ConfigStatus status = 1 [(udpa.annotations.field_migrate).oneof_promotion = "status_config"];
 
   // Client config status is populated by xDS clients. Will not be present if
   // the CSDS server is an xDS server. No matter what the client config status
   // is, xDS clients should always dump the most recent accepted xDS config.
-  ClientConfigStatus client_status = 7;
+  ClientConfigStatus client_status = 7
+      [(udpa.annotations.field_migrate).oneof_promotion = "status_config"];
 
   oneof per_xds_config {
     admin.v3.ListenersConfigDump listener_config = 2;