chore: update helm repo url

[juzhiyuan]

Resolve #852 (comment)

[bzp2010]

While I approve it, I must point out: even if you modify the latest chart, you can't stop resolving that domain because the old helm in the index file of the helm repo is still using that old address, and unresolving it will cause people using the old helm chart to encounter errors. ref: https://github.com/apache/apisix-helm-chart/blob/gh-pages/index.yaml

I'm afraid you'll need to modify or rebuild the repository index if you want to fix this. Or maybe we can switch to Helm OCI mode. I.e., let Helm chart be hosted by Docker Hub.

[juzhiyuan]

Or maybe we can switch to Helm OCI mode. I.e., let Helm chart be hosted by Docker Hub.

I prefer OCI mode because it is widely used in other projects.

[bzp2010]

Both the strengths and weaknesses of the OCI are the absence of a central index file.
Because there is no central index, we don't need to consider how to host it or maintain a registry. Very simple for maintenance.
Because there is no central index, the user must find the desired version on their own, and services like Argo CD can't find the full list of previous versions directly through the central index, which has more overhead.