Update vtgate.md

content/en/docs/14.0/reference/programs/vtgate.md

@@ -81,6 +81,7 @@ The following global options apply to `vtgate`:
 | --grpc_server_keepalive_enforcement_policy_min_time | duration | grpc server minimum keepalive time (default 5m0s) |
 | --grpc_server_keepalive_enforcement_policy_permit_without_stream | boolean | grpc server permit client keepalive pings even when there are no active streams (RPCs) |
 | --grpc_use_effective_callerid | boolean | If set, and SSL is not used, will set the immediate caller id from the effective caller id's principal. |
+| --grpc-use-static-authentication-callerid | boolean | If set, will set the immediate caller id to the username authenticated by the static auth plugin. |
 | --healthcheck_retry_delay | duration | health check retry delay (default 2ms) |
 | --healthcheck_timeout | duration | the health check timeout period (default 1m0s) |
 | --jaeger-agent-host | string | host and port to send spans to. if empty, no tracing will be done |