LCB_ERR_INVALID_ARGUMENT for all cluster HTTP requests when underscore in hostname

https://issues.couchbase.com/browse/CC-37

https://forums.couchbase.com/t/trouble-querying-but-can-get-documents/30419

The error comes from https://github.com/couchbase/libcouchbase/blob/0cddb2cdaf3a8004b72f063bc051dc4a9b604f6a/src/http/http.cc#L475-L477

This code snippet fails

std::string host = "https://yihyl6h_6wb3iarn.0ytsozyq2p9rg6ah.cloud.couchbase.com:18093/query/service/";
struct http_parser_url url_info {
};
auto rc = _lcb_http_parser_parse_url(host.data(), host.size(), 0, &url_info);
ASSERT_EQ(0, rc);

Remove the _ in the hostname and it passes