Re: remove nginx from https response header

See ngx_http_v2_filter_module.c;

(218 ) len += 1 + clcf->server_tokens ? ngx_http_v2_literal_size(NGINX_VER)
(411 ) *pos++ = NGX_HTTP_V2_ENCODE_RAW | (sizeof(NGINX_VER) - 1);
(412 ) pos = ngx_cpymem(pos, NGINX_VER, sizeof(NGINX_VER) - 1);