Use text/plain content-type and accept headers for cat APIs

[russcam]

This commit updates the api_generator to set text/plain content-type and accept headers by default for all cat APIs.

It also introduces a read_body_as_text async fn on Response to be able to treat the response body as plain text

Closes #71

[russcam]

Not overly keen on the fn name read_body_as_text() but named it in line with the existing read_body. I am considering breaking here and renaming them simply to text() and json(), respectively, which would mirror reqwest.

[mwilliammyers]

I agree, I like text() and json() better. Would we change read_body() if we went with text() and json()?

[russcam]

Would we change read_body() if we went with text() and json()?

Yeah, I was thinking

• read_body would become json
• read_body_as_text would become text

[mwilliammyers]

Oh haha, duh 🙃

Yeah, I vote for that.

[russcam]

Merged this in and opened #74 for the renaming breaking change

[russcam]

Labelled this also a breaking change as the default response format for cat APIs is now plain text