misspelling

Author: andreGarvin

upgrade workflow.md

@@ -6,7 +6,7 @@ client->>server: dial upgrade
 client->>server: upgrade ping probe
 server->>client: upgrade pong probe
 client->>client: pause old conn
-client->>client: swithc old conn to upgraded conn
+client->>client: switch old conn to upgraded conn
 client->>server: upgrade
 server->>server: pause old conn(return noop if waiting)
 server->>server: switch old conn to upgraded conn