fix: update React DOM to use edge (#776)

async hooks won't be supported and are discouraged, the edge version of React DOM doesn't use async hooks.

example/functions/src/ssr.ts

@@ -1,6 +1,6 @@
 import fs from "fs/promises";
 import App from "./react/App";
-import ReactDOMServer from "react-dom/server";
+import ReactDOMServer from "react-dom/server.edge";
 
 import React from "react";
 import API from "./api";