[Helm Chart Issue] apisix.proxy_cache.cache_ttl from values.yaml not applied to config.yaml

[Suhan-Powertask]

Describe the bug

When installing Apache APISIX using the official Helm chart,
the proxy_cache.cache_ttl value defined in values.yaml is not applied.
The generated config.yaml inside the ConfigMap still shows cache_ttl: 10s,
even when a custom TTL (e.g. 20s) is specified.

Steps to reproduce

1. Deploy APISIX using Helm or Terraform Helm provider.
2. Set the following in values.yaml:

   apisix:
     proxy_cache:
       cache_ttl: 20s

3. helm upgrade

Then check the generated ConfigMap:

kubectl -n apisix get cm apisix -o yaml | grep cache_ttl

You will still see:

cache_ttl: 10s

---

This issue makes it difficult to fine-tune proxy cache behavior in production deployments.
Even when a higher TTL (e.g., 20s or 60s) is specified, APISIX always defaults to 10 seconds
because the Helm chart template doesn’t pass the custom value into the ConfigMap.

Adding support for .Values.apisix.proxy_cache.cache_ttl would make the Helm chart more flexible and consistent with other configurable parameters.

[abdush]

Would be nice to merge this with the feature request here: #802

any plans to make this feature available soon?