CORS preflight responses are missing caching headers

[developit]

Describe the bug

When using bugsnag-js, the CORS POST requests sent to https://notify.bugsnag.com are missing the Access-Control-Max-Age response header. Without this, preflight responses are only cached for 5 seconds. There is no reason not to cache these for as long as possible - they are identical requests with no Bugsnag-related auth/parameters/headers.

Bugsnag's HTTP response to a CORS OPTIONS preflight should include Access-Control-Max-Age: 86400.
This will allow browsers to skip making repeated identical preflights to get identical responses.

Steps to reproduce

1. Go to any website using bugsnag-js
2. Trigger an error
3. Wait 5 seconds
4. Trigger another error
5. Observe that two identical preflight OPTIONS requests are sent:

Environment

• Bugsnag version: all (this is an issue with Bugsnag's servers)
• Browser framework version: all
• Server framework version: N/A
• Browser version: all browsers
• Device: all devices

[mclack]

Hi @developit

Thanks for raising this. We've added a task to our backlog to look into changing this when priorities allow.

We'll make sure to post any future updates regarding this here.