docs: update Cloudflare worker itty router link example (supabase#29904)

fix: 404 link for the cloudflare worker itty router

Author: mayur9210

examples/with-cloudflare-workers/README.md

@@ -68,7 +68,7 @@ return new Response(JSON.stringify(data), {
 
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-[👉 Next lesson](/04-proxy-supabase-requests-with-cloudflare-workers-and-itty-router)
+[👉 Next lesson](https://github.com/dijonmusters/supabase-data-at-the-edge/tree/main/04-proxy-supabase-requests-with-cloudflare-workers-and-itty-router)
 
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