DO Apps - "App Spec" .yaml help with adding CORS

Hello I have a static App on DO using the App importing from a GIT repository.

I have followed the instructions here including the .yaml file example but it keeps getting rejected

https://docs.digitalocean.com/products/app-platform/reference/app-spec/

alerts:
- rule: DEPLOYMENT_FAILED
- disabled: true
  rule: DOMAIN_FAILED
- disabled: true
  rule: DEPLOYMENT_STARTED
- disabled: true
  rule: DEPLOYMENT_CANCELED
- rule: DEPLOYMENT_LIVE
- disabled: true
  rule: DOMAIN_LIVE
domains:
- domain: mywebsite.uk
  type: PRIMARY
ingress:
  rules:
  - component:
      name: mywebsite-web-app-staging
    match:
      path:
        prefix: /
name: mywebsite-app-staging
region: lon
services:
- cors:
    allow_origins:
    - prefix: https://api.mywebsite.com
static_sites:
- catchall_document: index.html
  environment_slug: html
  github:
    branch: main
    deploy_on_push: true
    repo: xxxx/mywebsite-web-app-staging
  name: mywebsite-web-app-staging
  source_dir: /

Above is a copy of the .yaml the system produces with only the

services:
- cors:
    allow_origins:
    - prefix: https://api.mywebsite.com

added.

Thanks