The Umbraco Heartcore headless client library uses a vulnerable Refit dependency package

Summary

### Impact The Heartcore headless client library depends on [Refit ](https://github.com/reactiveui/refit) to assist in making HTTP requests to Heartcore public APIs. Refit recently published an advisory regarding a CRLF injection vulnerability whereby it is possible for a malicious user to smuggle additional headers or potentially body content into a request. This shouldn't affect Heartcore client library usage as the vulnerable method - `HttpHeaders.TryAddWithoutValidation` - is not used. However, since Refit is a transient dependency for applications using this library, then any users making direct use of Refit could be vulnerable. ### Patches The vulnerable version of Refit has been upgraded to a secure version, as of Umbraco.Headless.Client.Net version 1.5.0, available on [Nuget](https://www.nuget.org/packages/Umbraco.Headless.Client.Net/1.5.0). ### Workarounds If calling Refit from your own code, set any necessary HTTP headers without use of `HttpHeaders.TryAddWithoutValidation`. ### References See the [original Refit advisory](https://github.com/reactiveui/refit/security/advisories/GHSA-3hxg-fxwm-8gf7) for further info.