Fix Next.js version from 13 to 14 in README and docs (#431)

Author: sommeeeer

README.md

@@ -22,7 +22,7 @@ OpenNext takes the Next.js build output and converts it into a package that can
 
 ## Features
 
-OpenNext aims to support all Next.js 13 features. Some features are work in progress. Please open a [new issue](/issues/new) to let us know!
+OpenNext aims to support all Next.js 14 features. Some features are work in progress. Please open a [new issue](/issues/new) to let us know!
 
 - [x] App & Pages Router
 - [x] API routes

docs/pages/index.mdx

@@ -40,7 +40,7 @@ Closed source SaaS products like [Amplify](https://aws.amazon.com/amplify/) have
 We need your help keeping it up to date and feature complete. Make sure to [**join us on Discord**](https://sst.dev/discord) and [**star us on GitHub**](https://github.com/sst/open-next).
 ## Features
 
-OpenNext aims to support all Next.js 13 features. Some features are work in progress. Please open a [new issue](https://github.com/sst/open-next/issues/new) to let us know!
+OpenNext aims to support all Next.js 14 features. Some features are work in progress. Please open a [new issue](https://github.com/sst/open-next/issues/new) to let us know!
 
 - [x] App & Pages Router
 - [x] API routes