curl shows "Unsupported HTTP version (0.0) in response" on HTTP 403 responses

[muzso]

Test command:

curl -SsfL -D - --proxy-insecure -k -x "https://127.0.0.1:8090" "https://httpbin.org/status/403"

This will produce the following error:

HTTP/1.1 200 OK
Date: Tue, 27 Feb 2024 01:53:48 GMT
Transfer-Encoding: chunked

curl: (1) Unsupported HTTP version (0.0) in response

Btw. most requests through the proxy end up with this error message.
It's quite rare that a response gets back from the targeted URL.

If I run curl with trace enabled, I don't see any HTTP response from the targeted server at all.
See the attached curl_trace_ascii.txt for the output of the following command:

curl --trace-ascii - --proxy-insecure -k -x "https://127.0.0.1:8090" "https://httpbin.org/status/403" > curl_trace_ascii.txt 2>&1

[muzso]

Btw. with the official 0.3.0 release binary I get the same error as described in #178.
And I don't mean Docker! I run the binary as downloaded from https://github.com/nfx/slrp/releases/download/v0.3.0/slrp_0.3.0_linux_amd64.tar.gz and it produces the same error as described in the GH issue.

So I used the code from this PR: #191
It allowed me to actually start slrp.