cloudflare: fix package name (#65)

Author: vicb

pages/cloudflare/get-started.mdx

@@ -173,7 +173,7 @@ This includes:
 You can continue to run `next dev` when developing locally.
 
 Modify your Next.js configuration file to import and call the `initOpenNextCloudflareForDev` utility
-from the `@cloudflare/next-on-pages` package. This makes sure that the Next.js dev server can optimally integrate with the open-next
+from the `@opennextjs/cloudflare` package. This makes sure that the Next.js dev server can optimally integrate with the open-next
 cloudflare adapter and it is necessary for using bindings during local development.
 
 This is an example of a Next.js configuration file calling the utility: