chore: upgrade apisix to 3.16.0

[shreemaan-abhishek]

Summary

• Upgrades Apache APISIX from 3.15.0 to 3.16.0 (chart version 2.13.0 → 2.14.0)
• Adds support for apisix.nginx.metaLuaSharedDicts to override meta-level lua_shared_dict settings in the generated nginx_config

Why meta-level shared dict support?

APISIX 3.16.0 (PR #12996) moved the upstream-healthcheck shared memory dict from nginx_config.http.lua_shared_dict to nginx_config.meta.lua_shared_dict, making it shared across both the HTTP and stream subsystems. Previously, users who needed to customize the upstream-healthcheck dict size could do so via apisix.nginx.luaSharedDicts. After this APISIX change, that override would silently stop working. The new metaLuaSharedDicts value allows users to override meta-level shared dicts.

Notable APISIX 3.16.0 changes

Breaking changes (plugin-level defaults, no helm chart config needed):

• ssl_verify default in openid-connect plugin changed to true (#13010)
• tencent-cloud-cls scheme default changed to https (#13009)

Full changelog: https://github.com/apache/apisix/blob/master/CHANGELOG.md#3160

Test plan

• helm template renders correctly with default values (no meta section when metaLuaSharedDicts is empty)
• helm template renders meta.lua_shared_dict when metaLuaSharedDicts is set
• Verify APISIX 3.16.0 container image apache/apisix:3.16.0-ubuntu exists
• Deploy and confirm APISIX starts correctly with the new chart