Update README.md (#19103)

Correct the example endpoint to `/oak-server/greet`

examples/edge-functions/supabase/functions/oak-server/README.md

@@ -8,10 +8,10 @@ This example shows how you can write functions using Oak server middleware (http
 supabase functions serve --no-verify-jwt
 ```
 
-Use cURL or Postman to make a POST request to http://localhost:54321/functions/v1/oak-server.
+Use cURL or Postman to make a POST request to http://localhost:54321/functions/v1/oak-server/greet.
 
 ```
-  curl --location --request POST 'http://localhost:54321/functions/v1/oak-server' \
+  curl --location --request POST 'http://localhost:54321/functions/v1/oak-server/greet' \
 --header 'Authorization: Bearer YOUR_TOKEN' \
 --header 'Content-Type: application/json' \
 --data-raw '{ "name": "John Doe" }'