Empty response to updates to the renewal-info resource (ARI) causes error to be reported

[jre-lsft]

I'm currently evaluating win-acme 2.2.3 (using the Let's Encrypt staging environment).
While testing the renewal process, I noticed that for each certificate renewed, an error was reported regarding the recently added ARI capability to inform the ACME server that the ACME client no longer cares about a particular certificate:

Error updating renewal info: The input does not contain any JSON tokens. Expected the input to start with a valid JSON token, when isFinalBlock is true. Path: $ | LineNumber: 0 | BytePositionInLine: 0.

This error is caused by passing an empty string to the JSON deserializer because win-acme's fork of ACMESharpCore expects a non-empty response for updates to the renewal-info resource:
https://github.com/win-acme/ACMESharpCore/blob/797daac409bfbe9f89aa1dfb474e27782563bda8/src/ACMESharp/Protocol/AcmeProtocolClient.cs#L476

However, Let's Encrypt responds with an empty body, which actually seems to conform to section 4.2 of draft-ietf-acme-ari-00.
win-acme's fork of ACMESharpCore should not expect the HTTP response to carry a non-empty body.
I will follow up shortly with pull request.