add debug logging

src/http/modules/ngx_http_browser_module.c

diff --git a/src/http/modules/ngx_http_browser_module.c b/src/http/modules/ngx_http_browser_module.c
index 390b62f..e0710c1 100644
--- a/src/http/modules/ngx_http_browser_module.c
+++ b/src/http/modules/ngx_http_browser_module.c
@@ -318,6 +318,10 @@
                 if (c == '.') {
                     version += ver * scale;
 
+                    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                                   "version: \"%ui\" \"%ui\"",
+                                   modern[i].version, version);
+
                     if (version > modern[i].version) {
                         return NGX_HTTP_MODERN_BROWSER;
                     }