http: add connect code into auth challenge detection

src/sys/libcurl.zig

@@ -178,6 +178,7 @@ pub const CurlInfo = enum(c.CURLINFO) {
     private = c.CURLINFO_PRIVATE,
     redirect_count = c.CURLINFO_REDIRECT_COUNT,
     response_code = c.CURLINFO_RESPONSE_CODE,
+    connect_code = c.CURLINFO_HTTP_CONNECTCODE,
 };
 
 pub const Error = error{
@@ -662,6 +663,7 @@ pub fn curl_easy_getinfo(easy: *Curl, comptime info: CurlInfo, out: anytype) Err
             break :blk c.curl_easy_getinfo(easy, inf, p);
         },
         .response_code,
+        .connect_code,
         .redirect_count,
         => blk: {
             const p: *c_long = out;