nghttpx: Announce 2.0 in via header field

src/shrpx_http2_session.cc

@@ -880,10 +880,8 @@ int on_response_headers(Http2Session *http2session,
   }
   downstream->set_response_http_status(strtoul(status->second.c_str(),
                                                nullptr, 10));
-  // Just assume it is HTTP/1.1. But we really consider to say 2.0
-  // here.
-  downstream->set_response_major(1);
-  downstream->set_response_minor(1);
+  downstream->set_response_major(2);
+  downstream->set_response_minor(0);
 
   auto content_length = http2::get_header(nva, "content-length");
   if(!content_length && downstream->get_request_method() != "HEAD" &&

src/shrpx_http2_upstream.cc

@@ -229,6 +229,11 @@ int on_begin_headers_callback(nghttp2_session *session,
   upstream->add_downstream(downstream);
   downstream->init_response_body_buf();
 
+  // Although, we deprecated minor version from HTTP/2, we supply
+  // minor version 0 to use via header field in a conventional way.
+  downstream->set_request_major(2);
+  downstream->set_request_minor(0);
+
   return 0;
 }
 } // namespace