* style: Use fmt.Sprint without formating

* fix pipeline

)

As noted in #743, some users of the `openapi3filter`, largely via
`oapi-codegen` and `openapi.tanna.dev/go/validator`[0] are seeing that
when using an `AuthenticationFunc`, this can lead to errors such as:

    request body has an error: value is required but missing

Or:

    request body has an error: reading failed: http: invalid Read on closed Body

This turns out to be down to the fact that a call to the
`AuthenticationFunc` may read the request body, but due to the way that
Go's `io.Reader`s can only be read once, this then means the body cannot
be read by anyone else further in the request chain.

To resolve this, we can make sure that each iteration of the
`AuthenticationFunc` gets a fresh copy of the request body (in its own
`io.Reader`).

This follows logic that exists within the `ValidateRequestBody` method,
with an additional layer of caching the raw bytes from the body.

We also add tests to validate:

- calling the `ValidateRequest` body function with an
  `AuthenticationFunc` that reads the request body
- using an integration test with a test HTTP server also works,
  indicating that the HTTP handler can then read the request body itself

Closes #743.

[0]: https://gitlab.com/jamietanna/httptest-openapi/-/issues/5

* Introduce fix for refs on items within additional properties

* Remove space

---------

Co-authored-by: Robert Hoppe <robert.hoppe@mail.schwarz>