chore(website): update middleware page (#343)

In nextjs version 15, cookies is async
https://nextjs.org/docs/app/api-reference/functions/cookies

Author: CauaYves

website/docs/define-actions/middleware.md

@@ -75,7 +75,8 @@ export const authActionClient = actionClient
   // Define authorization middleware.
   // highlight-start
   .use(async ({ next }) => {
-    const session = cookies().get("session")?.value;
+    const cookieStore = await cookies();
+    const session = cookieStore.get("session")?.value;
 
     if (!session) {
       throw new Error("Session not found!");
@@ -265,4 +266,4 @@ export const actionClientWithMyMiddleware = actionClient.use(myMiddleware1).use(
 
 An action defined using the `actionClientWithMyMiddleware` will contain `foo`, `baz` and `john` in its context.
 
-\* Note that you can pass, **but not required to**, an object with three generic properties to the `createMiddleware()` function: `ctx` \[1\], `metadata` \[2\] and `serverError` \[3\]. Those keys are optional, and you should only provide them if you want your middleware to require **at minimum** the shape you passed in as generic. By doing that, following the above example, you can then access `ctx.foo` and `metadata.actionName` in the middleware you're defining, and by awaiting the `next` function you'll see that `serverError` is an object with the `message` property. If you pass a middleware that requires those properties to a client that doesn't have them, you'll get an error in `use()` method.
+\* Note that you can pass, **but not required to**, an object with three generic properties to the `createMiddleware()` function: `ctx` \[1\], `metadata` \[2\] and `serverError` \[3\]. Those keys are optional, and you should only provide them if you want your middleware to require **at minimum** the shape you passed in as generic. By doing that, following the above example, you can then access `ctx.foo` and `metadata.actionName` in the middleware you're defining, and by awaiting the `next` function you'll see that `serverError` is an object with the `message` property. If you pass a middleware that requires those properties to a client that doesn't have them, you'll get an error in `use()` method.