tests: bumped the NGINX core to 1.29.4.

Author: zhuizhuhaomeng

.travis.yml

@@ -51,7 +51,7 @@ env:
     - TEST_NGINX_RANDOMIZE=1
     - LUACHECK_VER=0.21.1
   matrix:
-    - NGINX_VERSION=1.29.2 OPENSSL_VER=3.5.4 OPENSSL_PATCH_VER=3.5.4
+    - NGINX_VERSION=1.29.4 OPENSSL_VER=3.5.4 OPENSSL_PATCH_VER=3.5.4
 
 services:
   - memcache