Feature: Headers support for OpenApi and Postman parsers

[nikspyratos]

Based on your guidance in #9 I poked around with getting headers working for the OpenApiParser. After a little more digging and using a postman collection for the same API I'm building for, I added header parsing to the Postman parser too.

While I see named parameters are in use here, juuuust to be safe I've added the header parameter arrays to the end of the argument list instead of anywhere else.

Let me know what you think, or if you have any issues with any API specs/collections you have?

[HelgeSverre]

This seems to also generate arguments for common headers that Saloon already handles:

Authorization
Content-Type
Accept

I'd like to see a blacklist of headers Saloon already handles before merging this :)

See:

• https://docs.saloon.dev/the-basics/connectors#default-headers-and-query-parameters
• https://docs.saloon.dev/the-basics/headers

[nikspyratos]

I haven't forgotten about this, just life's a bit busy right now 😅

[HelgeSverre]

No worries :)

[nikspyratos]

Heyo @HelgeSverre I've added some basic exclusion to the parsers, let me know what you think or if you'd prefer some edits/style changes. Tried it out with the latest version of the openapi spec I initially mentioned and the Stripe postman collection.