fix: react tutorial entrypoint ./main.ts to server/main.ts (#1359)

Author: NoonKnight

examples/tutorials/react.md

@@ -386,7 +386,7 @@ then deploy the app by connecting your GitHub repository and selecting the
 branch you want to deploy.
 
 Give the project a name, and make sure that the `build step` is set to
-`deno run build` and the `Entrypoint` is `./main.ts`.
+`deno run build` and the `Entrypoint` is `server/main.ts`.
 
 Click the `Deploy Project` button and your app will be live!