CORS issue for serverless-http

[Slava-Ini]

It seems that there is no way to properly set the CORS headers using serverless-http for netlify.
For the case with AWS it's possible to configure headers in serverless.yaml, but for netlify header config used in netlify.toml and _headers somehow gets overwritten by serverless-http, so after successful preflight, you would still get CORS error while sending request from other origin.