Request cancellation implemented in cats-effect

[istreeter]

Hi maintainers, this is just to make you aware of a PR I opened in cats-effect: typelevel/cats-effect#4375

The PR is directly relevant to http4s-jdk-http-client, because it changes what happens when a request is cancelled when using this library.

This is the code I tested with:

client.expect[String](request).timeoutTo(1.second, IO.unit)

Without my cats-effect PR, I can see in wireshark the HTTP request runs to completion after 5 seconds, even though .timeoutTo cancelled the cats-effect fiber after 1 second. After my PR, I can see in wireshark the network request is cancelled after 1 second. For HTTP/1 I see a RST which closes the TCP connection. For HTTP/2 I see a RST_STREAM which cancels the request without closing the TCP connection.