fix(types): accept userInfo in generateCsrf

[ojeytonwilliams]

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

Aside from updating the docs, I think this closes #150

[gurgunday]

Is there a unit test for this?

And why not add the option to fastifyCsrfProtection.CookieSerializeOptions?

[mcollina]

lgtm

this is ok, there is a test for the type

[ojeytonwilliams]

And why not add the option to fastifyCsrfProtection.CookieSerializeOptions?

userInfo isn't connected to the cookies, it's just passed to @fastify/csrf when creating a token. I don't think it's correct to combine the types.

[gurgunday]

lgtm