refactor: export the nextTick helper method

Related: socketio/socket.io-client#1551

Author: darrachequesne

lib/index.ts

@@ -7,3 +7,4 @@ export { Transport } from "./transport.js";
 export { transports } from "./transports/index.js";
 export { installTimerFunctions } from "./util.js";
 export { parse } from "./contrib/parseuri.js";
+export { nextTick } from "./transports/websocket-constructor.js";